Question

a sequence of transformations is described below.

• a translation
• a dilation about a point \\(p\\)
• another translation
• a rotation about the point \\(p\\)

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 individual transformations

Using the Geometric Transformations knowledge point, we evaluate each transformation in the sequence.

• Translations in Geometry and Rotations in Geometry are rigid transformations.
• A dilation is a non-rigid transformation.

Determine properties preserved by rigid transformations

Using the Rigid Transformations knowledge point, translations and rotations preserve:

• Segment lengths (distance)
• Angle measures

Determine properties preserved by dilations

Using the Non-rigid Transformations knowledge point, a dilation about a point \(P\) changes the size of a figure.

• Segment lengths are scaled by a scale factor and are not preserved.
• Angle measures remain equal (similarity is preserved).

Combine the sequence of transformations

Since the sequence contains a dilation, segment lengths are not preserved overall. However, because every transformation in the sequence (translations, dilation, and rotation) preserves angle measures, the overall sequence must preserve angle measures.

Select the correct option

Since only angle measures are preserved, the correct choice is "Angle measures only".

Answer:

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