Question

8th grade math geometry study guide
8.g.1.b - angles map to angles of the same measure

1. can - show that angle measures are preserved under rigid motions.

directions: show all work in the workspace provided.

notes & vocabulary:

• angle measure is invariant under translations, reflections, and rotations.
• orientation may change, but measure remains the same.
• right/acute/obtuse classifications are preserved.

problem 1: \\(\angle abc = 75^{circ}\\). reflect \\(\triangle abc\\) across x - axis. what is \\(m\angle abc\\)?

reflect \\(\triangle abc\\) across x - axis

answer:

Explanation:

Step1: Recall angle - measure property

Angle measure is invariant under reflections.

Step2: Apply the property

Since \(\angle ABC = 75^{\circ}\) and reflection preserves angle - measure, when \(\triangle ABC\) is reflected across the \(x\) - axis to get \(\triangle A'B'C'\), \(\angle A'B'C'=\angle ABC\).

Answer:

\(75^{\circ}\)