Question

a sequence of transformations is described below.

• a reflection over a line \\(\overleftrightarrow{pq}\\)
• a rotation about the point \\(p\\)
• another reflection over \\(\overleftrightarrow{pq}\\)
• a rotation about the point \\(q\\)

which of the following must be preserved under this sequence of transformations?

choose 1 answer:

(a) angle measures only
(b) segment lengths only
(c) both angle measures and segment lengths
(d) neither angle measures nor segment lengths

Explanation:

Analyze the given sequence of transformations

Using the Geometric Transformations knowledge point, we identify the individual operations in the sequence:

1. A reflection over a line \(\overleftrightarrow{PQ}\)
2. A rotation about the point \(P\)
3. Another reflection over \(\overleftrightarrow{PQ}\)
4. A rotation about the point \(Q\)

Classify the types of transformations

Using the Rigid Transformations knowledge point

• Reflections and rotations are both classified as rigid transformations (or isometries).
• Rigid transformations preserve both distance (segment lengths) and angle measures.
• Any sequence of rigid transformations is also a rigid transformation and must preserve both properties.

Evaluate the given options

• Since the entire sequence consists solely of rigid transformations, both segment lengths and angle measures must be preserved.
• Therefore, option (C) is the correct choice.

Answer:

• (A) Angle measures only
• (B) Segment lengths only
• (C) Both angle measures and segment lengths (Correct answer)
• (D) Neither angle measures nor segment lengths