QUESTION IMAGE
Question
14 which pairs of angles are alternate exterior angles? image of two parallel lines l and m cut by a transversal n, with angles labeled 1,2,3,4 (at intersection with l) and 5,6,7,8 (at intersection with m) a ∠1, ∠6 b ∠2, ∠4 c ∠2, ∠7 d ∠3, ∠6 e ∠3, ∠8 f ∠4, ∠8
Step1: Recall Alternate Exterior Angles Definition
Alternate exterior angles are two angles that lie outside the two lines (l and m) and on opposite sides of the transversal (n). They are formed when a transversal crosses two parallel lines (or any two lines).
Step2: Analyze Each Option
- Option A: ∠1, ∠6
∠1 is above line l (exterior), ∠6 is below line m (interior? Wait, no: line m has angles 5,6 (above) and 7,8 (below). Wait, ∠6 is below line m? No, looking at the diagram: line m is horizontal, transversal n crosses it. Angles 5,6 are above and below? Wait, no, the diagram: for line l, angles 1,2 (above), 3,4 (below). For line m, angles 8,5 (above), 7,6 (below). Transversal n is the slanted line. So exterior angles are those outside the region between l and m. So ∠1 is outside (above l), ∠6 is below m (outside the l - m region). But are they on opposite sides of transversal? ∠1 is left of transversal? Wait, transversal n: left side of n (from the intersection with l: ∠1, ∠4 are left; ∠2, ∠3 right. For line m: ∠8, ∠7 left; ∠5, ∠6 right. So alternate exterior: outside l and m, opposite sides of n. So ∠2 (right of n, above l) and ∠7 (left of n, below m)? Wait, no, let's re - examine:
Wait, the correct definition: alternate exterior angles are non - adjacent, outside the two lines, and on opposite sides of the transversal.
Let's list the angles:
- Line l (top line), line m (bottom line), transversal n (slanted).
Exterior to the two lines (l and m) are angles: ∠1, ∠2 (above l), ∠7, ∠6 (below m). Wait, no: between l and m is the middle region. So outside are ∠1, ∠2 (above l) and ∠7, ∠6 (below m).
Now, opposite sides of transversal n:
- Left side of n: ∠1, ∠4 (on l), ∠8, ∠7 (on m).
- Right side of n: ∠2, ∠3 (on l), ∠5, ∠6 (on m).
So alternate exterior angles should be one on left side (outside l - m) and one on right side (outside l - m), and not adjacent.
- Option A: ∠1 (left of n, above l) and ∠6 (right of n, below m). Wait, ∠6 is right of n, below m. ∠1 is left of n, above l. Are they alternate exterior? Wait, maybe I made a mistake. Let's check other options.
- Option B: ∠2, ∠4
∠2 and ∠4 are adjacent (vertical angles? No, ∠2 and ∠4: ∠2 is above l, right of n; ∠4 is below l, left of n. They are vertical angles? No, vertical angles are opposite. Wait, ∠1 and ∠3 are vertical? No, ∠1 and ∠3: no, ∠1 and ∠3 are adjacent? Wait, no, at the intersection of l and n: ∠1 + ∠2 = 180, ∠3 + ∠4 = 180, ∠1 and ∠3 are vertical? Wait, no, ∠1 and ∠3: actually, ∠1 and ∠3 are vertical angles? Wait, no, ∠1 and ∠3: when two lines intersect, vertical angles are opposite. So at l and n intersection: ∠1 and ∠3 are vertical? No, ∠1 and ∠3: ∠1 is top - left, ∠3 is bottom - right. Wait, no, the intersection: ∠1 (top - left), ∠2 (top - right), ∠3 (bottom - right), ∠4 (bottom - left). So ∠1 and ∠3 are not vertical. ∠1 and ∠4 are adjacent (supplementary), ∠2 and ∠3 are adjacent. ∠2 and ∠4: are they alternate interior? No, they are on different sides but ∠2 is above l, ∠4 is below l. But they are not exterior. So B is incorrect.
- Option C: ∠2, ∠7
∠2 is above l, right of transversal n. ∠7 is below m, left of transversal n. They are outside the two lines (l and m) and on opposite sides of the transversal n. So this fits the definition of alternate exterior angles.
- Option D: ∠3, ∠6
∠3 is below l, right of n (interior to l - m region? Wait, l and m are horizontal lines, the region between them is between l (top) and m (bottom). ∠3 is below l (so in the l - m region? Wait, l is top line, m is bottom line. So between l and m i…
Snap & solve any problem in the app
Get step-by-step solutions on Sovi AI
Photo-based solutions with guided steps
Explore more problems and detailed explanations
Step1: Recall Alternate Exterior Angles Definition
Alternate exterior angles are two angles that lie outside the two lines (l and m) and on opposite sides of the transversal (n). They are formed when a transversal crosses two parallel lines (or any two lines).
Step2: Analyze Each Option
- Option A: ∠1, ∠6
∠1 is above line l (exterior), ∠6 is below line m (interior? Wait, no: line m has angles 5,6 (above) and 7,8 (below). Wait, ∠6 is below line m? No, looking at the diagram: line m is horizontal, transversal n crosses it. Angles 5,6 are above and below? Wait, no, the diagram: for line l, angles 1,2 (above), 3,4 (below). For line m, angles 8,5 (above), 7,6 (below). Transversal n is the slanted line. So exterior angles are those outside the region between l and m. So ∠1 is outside (above l), ∠6 is below m (outside the l - m region). But are they on opposite sides of transversal? ∠1 is left of transversal? Wait, transversal n: left side of n (from the intersection with l: ∠1, ∠4 are left; ∠2, ∠3 right. For line m: ∠8, ∠7 left; ∠5, ∠6 right. So alternate exterior: outside l and m, opposite sides of n. So ∠2 (right of n, above l) and ∠7 (left of n, below m)? Wait, no, let's re - examine:
Wait, the correct definition: alternate exterior angles are non - adjacent, outside the two lines, and on opposite sides of the transversal.
Let's list the angles:
- Line l (top line), line m (bottom line), transversal n (slanted).
Exterior to the two lines (l and m) are angles: ∠1, ∠2 (above l), ∠7, ∠6 (below m). Wait, no: between l and m is the middle region. So outside are ∠1, ∠2 (above l) and ∠7, ∠6 (below m).
Now, opposite sides of transversal n:
- Left side of n: ∠1, ∠4 (on l), ∠8, ∠7 (on m).
- Right side of n: ∠2, ∠3 (on l), ∠5, ∠6 (on m).
So alternate exterior angles should be one on left side (outside l - m) and one on right side (outside l - m), and not adjacent.
- Option A: ∠1 (left of n, above l) and ∠6 (right of n, below m). Wait, ∠6 is right of n, below m. ∠1 is left of n, above l. Are they alternate exterior? Wait, maybe I made a mistake. Let's check other options.
- Option B: ∠2, ∠4
∠2 and ∠4 are adjacent (vertical angles? No, ∠2 and ∠4: ∠2 is above l, right of n; ∠4 is below l, left of n. They are vertical angles? No, vertical angles are opposite. Wait, ∠1 and ∠3 are vertical? No, ∠1 and ∠3: no, ∠1 and ∠3 are adjacent? Wait, no, at the intersection of l and n: ∠1 + ∠2 = 180, ∠3 + ∠4 = 180, ∠1 and ∠3 are vertical? Wait, no, ∠1 and ∠3: actually, ∠1 and ∠3 are vertical angles? Wait, no, ∠1 and ∠3: when two lines intersect, vertical angles are opposite. So at l and n intersection: ∠1 and ∠3 are vertical? No, ∠1 and ∠3: ∠1 is top - left, ∠3 is bottom - right. Wait, no, the intersection: ∠1 (top - left), ∠2 (top - right), ∠3 (bottom - right), ∠4 (bottom - left). So ∠1 and ∠3 are not vertical. ∠1 and ∠4 are adjacent (supplementary), ∠2 and ∠3 are adjacent. ∠2 and ∠4: are they alternate interior? No, they are on different sides but ∠2 is above l, ∠4 is below l. But they are not exterior. So B is incorrect.
- Option C: ∠2, ∠7
∠2 is above l, right of transversal n. ∠7 is below m, left of transversal n. They are outside the two lines (l and m) and on opposite sides of the transversal n. So this fits the definition of alternate exterior angles.
- Option D: ∠3, ∠6
∠3 is below l, right of n (interior to l - m region? Wait, l and m are horizontal lines, the region between them is between l (top) and m (bottom). ∠3 is below l (so in the l - m region? Wait, l is top line, m is bottom line. So between l and m is the middle. ∠3 is below l (so above m? Wait, no, l is above m. So ∠3 is below l (so in the space between l and m) and ∠6 is below m (outside the l - m region). So ∠3 is interior, ∠6 is exterior. So not both exterior. Incorrect.
- Option E: ∠3, ∠8
∠3 is below l (interior to l - m region), ∠8 is above m (interior to l - m region? Wait, ∠8 is above m (so between l and m? Because l is above m. So ∠8 is above m (so in the l - m region) and ∠3 is below l (in the l - m region). So both interior. Incorrect.
- Option F: ∠4, ∠8
∠4 is below l (interior to l - m region), ∠8 is above m (interior to l - m region). Both interior, and same side? No, ∠4 is left of n, ∠8 is left of n. So same side. Incorrect.
Wait, also check Option A again: ∠1 (above l, left of n) and ∠6 (below m, right of n). Are they exterior? ∠1 is outside (above l), ∠6 is outside (below m). Opposite sides of n. But wait, in the standard diagram, alternate exterior angles for two parallel lines cut by a transversal are like ∠2 and ∠7, ∠1 and ∠6? Wait, maybe I made a mistake earlier. Wait, let's re - define:
Two lines (l and m) cut by transversal n. Exterior angles are those not between l and m. So for l: angles 1,2 (above l, so exterior to l - m) and 3,4 (below l, but between l and m? No, l is top, m is bottom. So between l and m is the area between them. So angles above l (1,2) and below m (6,7) are exterior. Angles between l and m are 3,4 (below l) and 5,8 (above m).
So alternate exterior angles: one above l (exterior), one below m (exterior), and on opposite sides of transversal n.
Transversal n: left side (∠1, ∠4, ∠8, ∠7) and right side (∠2, ∠3, ∠5, ∠6).
So:
- ∠1 (left, above l) and ∠6 (right, below m): alternate exterior?
- ∠2 (right, above l) and ∠7 (left, below m): alternate exterior?
Now, let's check the options. Option C is ∠2, ∠7 and Option A is ∠1, ∠6. Wait, maybe I misread the diagram. Wait, the diagram: line l is top, line m is bottom. Transversal n crosses l at the top intersection, m at the bottom intersection.
Angles at l - n intersection: ∠1 (top - left), ∠2 (top - right), ∠3 (bottom - right), ∠4 (bottom - left).
Angles at m - n intersection: ∠8 (top - left), ∠5 (top - right), ∠6 (bottom - right), ∠7 (bottom - left).
So exterior angles (outside l - m): ∠1, ∠2 (above l), ∠7, ∠6 (below m).
Alternate exterior:
- ∠1 (left of n, above l) and ∠6 (right of n, below m): opposite sides, exterior.
- ∠2 (right of n, above l) and ∠7 (left of n, below m): opposite sides, exterior.
Now, check the options:
Option A: ∠1, ∠6 – is this an option? Yes, Option A is ∠1, ∠6. Option C is ∠2, ∠7.
Wait, maybe the diagram has l and m as parallel. Let's recall the standard alternate exterior angles: for two parallel lines, alternate exterior angles are congruent. So in the diagram, if l || m, then ∠1 ≅ ∠6, ∠2 ≅ ∠7.
Now, looking at the options, Option C is ∠2, ∠7 and Option A is ∠1, ∠6. Wait, but in the given options, Option C is present and Option A is present? Wait, no, let's check the original options again:
Options:
A. ∠1, ∠6
B. ∠2, ∠4
C. ∠2, ∠7
D. ∠3, ∠6
E. ∠3, ∠8
F. ∠4, ∠8
So both A and C? But that can't be. Wait, maybe I made a mistake. Wait, let's check the definition again. Alternate exterior angles are two angles that are outside the two lines, on opposite sides of the transversal, and not adjacent.
For ∠2 and ∠7:
- ∠2 is outside the two lines (above l), ∠7 is outside the two lines (below m).
- ∠2 is on the right side of transversal n, ∠7 is on the left side of transversal n.
- They are not adjacent.
For ∠1 and ∠6:
- ∠1 is outside (above l), ∠6 is outside (below m).
- ∠1 is on the left side of transversal n, ∠6 is on the right side of transversal n.
- They are not adjacent.
But maybe the question considers the standard pairs. Wait, maybe the diagram is such that l and m are parallel, and the alternate exterior angles are ∠2 and ∠7, ∠1 and ∠6. But let's check the options. The options include C (∠2, ∠7) and A (∠1, ∠6). Wait, maybe I made a mistake in the initial analysis. Wait, let's check with a standard example:
In a standard parallel lines cut by transversal, alternate exterior angles are:
If the two lines are horizontal, transversal slanting, then:
Top line (l): angles 1 (top - left), 2 (top - right), 3 (bottom - right), 4 (bottom - left).
Bottom line (m): angles 5 (top - right), 6 (bottom - right), 7 (bottom - left), 8 (top - left).
Wait, no, maybe the numbering is different. Wait, the user's diagram: line l has ∠1 (top - left), ∠2 (top - right), ∠3 (bottom - right), ∠4 (bottom - left). Line m has ∠8 (top - left), ∠5 (top - right), ∠6 (bottom - right), ∠7 (bottom - left).
So transversal n goes from top - left (∠1) to bottom - right (∠6).
So exterior angles:
- Above l: ∠1, ∠2.
- Below m: ∠6, ∠7.
Alternate exterior:
- ∠1 (above l, left of n) and ∠6 (below m, right of n): alternate exterior.
- ∠2 (above l, right of n) and ∠7 (below m, left of n): alternate exterior.
Now, check the options:
Option A: ∠1, ∠6 – yes, alternate exterior.
Option C: ∠2, ∠7 – yes, alternate exterior.
Wait, but the original options: maybe the diagram is different. Wait, maybe I misread the angle numbers. Wait, the user's diagram: at line m, the angles are 8 (top - left), 5 (top - right), 7 (bottom - left), 6 (bottom - right). So ∠8 is above m (between l and m), ∠5 is above m (between l and m), ∠7 is below m (exterior), ∠6 is below m (exterior). At line l, ∠1 is above l (exterior), ∠2 is above l (exterior), ∠3 is below l (between l and m), ∠4 is below l (between l and m).
So alternate exterior angles must be one from {∠1, ∠2} (exterior above l) and one from {∠6, ∠7} (exterior below m), and on opposite sides of transversal n.
Transversal n: left side (∠1, ∠4, ∠8, ∠7) and right side (∠2, ∠3, ∠5, ∠6).
So:
- ∠1 (left, above l) and ∠6 (right, below m): opposite sides, exterior.
- ∠2 (right, above l) and ∠7 (left, below m): opposite sides, exterior.
Now, check the options:
Option A: ∠1, ∠6 – correct.
Option C: ∠2, ∠7 – correct.
But the problem is a multiple - choice, maybe there are two correct answers? Wait, the original question: "Which pairs of angles are alternate exterior angles?" So maybe both A and C? But let's check the options again. Wait, maybe I made a mistake in Option A: ∠6 is below m, but is ∠6 exterior? Yes, because it's below m (outside the l - m region). ∠1 is above l (outside the l - m region). Opposite sides of transversal.
But in the standard definition, alternate exterior angles are equal when lines are parallel, but the question doesn't say lines are parallel, just asks which pairs are alternate exterior (by definition).
Wait, maybe the diagram is such that l and m are parallel, and the intended answer is C (∠2, ∠7) and A (∠1, ∠6). But let's check the options again. The options are A to F. Let's re - evaluate:
- Option A: ∠1, ∠6. ∠1 is outside (above l), ∠6 is outside (below m). Opposite sides of transversal. Alternate exterior.
- Option C: ∠2, ∠7. ∠2 is outside (above l), ∠7 is outside (below m). Opposite sides of transversal. Alternate exterior.
Wait, maybe the question has two correct answers, but let's check the diagram again. Wait, maybe the user's diagram has l and m as parallel, and the alternate exterior angles are ∠2 and ∠7, ∠1 and ∠6. But let's see the options. If we have to choose one, maybe the intended answer is C (∠2, ∠7) or A (∠1, ∠6). Wait, maybe I made a mistake in the initial analysis of Option A. Let's check with the angle positions:
∠1 is at the top - left of the l - n intersection, ∠6 is at the bottom - right of the m - n intersection. They are on opposite sides of the transversal and outside the two lines. ∠2 is at the top - right of l - n, ∠7 is at the bottom - left of m - n, also opposite sides and outside.
But maybe the answer is C (∠2, ∠7) as a more standard pair. Alternatively, maybe A is wrong. Wait, let's check the definition again: alternate exterior angles are two angles that lie outside the two lines and on opposite sides of the transversal. So for ∠1 and ∠6: ∠1 is outside (above l), ∠6 is outside (below m). Transversal n: ∠1 is on the left side of n, ∠6 is on the right side of n. So they satisfy the definition. For ∠2 and ∠7: ∠2 is on the right side of n, ∠7 is on the left side of n, both outside. So both A and C are correct? But the options are given as A to F. Maybe the diagram is different. Wait, maybe the angle ∠6 is not exterior. Wait, no, ∠6 is below m, so outside the region between l and m.
Wait, perhaps the correct answers are A and C, but let's check the options again. The options are:
A. ∠1, ∠6
B. ∠2, ∠4
C. ∠2, ∠7
D. ∠3, ∠6
E. ∠3, ∠8
F. ∠4, ∠8
So if we follow the definition, both A and C