Question

for each triangle, check all that apply.
triangle a
5
5
4
triangle b
20
20
20
triangle c
9
6
12
scalene
isosceles
equilateral
scalene
isosceles
equilateral
scalene
isosceles
equilateral

Explanation:

Step1: Analyze Triangle A

Triangle A has sides 5, 5, 4. An isosceles triangle has at least two equal sides. Here, two sides are 5, so it's isosceles. Scalene has all sides different, so no. Equilateral has all sides equal, so no.

Step2: Analyze Triangle B

Triangle B has sides 20, 20, 20. An equilateral triangle has all sides equal, so it's equilateral (and also isosceles, since equilateral is a special case of isosceles). Scalene has all sides different, so no.

Step3: Analyze Triangle C

Triangle C has sides 9, 6, 12. All sides are different, so it's scalene. Isosceles has at least two equal sides, so no. Equilateral has all sides equal, so no.

Answer:

• Triangle A: Isosceles (check the Isosceles box)
• Triangle B: Isosceles, Equilateral (check both Isosceles and Equilateral boxes)
• Triangle C: Scalene (check the Scalene box)