Back to Angles are taken to angles of the same measure — Problem 3 · Task Set 20

Exercises: Rigid Motions Preserve Angle Measure

Work through each section in order. A rigid motion is a translation, reflection, or rotation. For each problem, decide what the angle-preservation property tells you before measuring or computing. Show your work where indicated.

Grade 8·21 problems·~30 min·Common Core Math - Grade 8·standard·8-g-a-1b

Work through problems with immediate feedback

Fluency Practice

Apply each transformation and verify the angle-preservation property. Use the measure of the original angle to predict the measure of the image.

$A coordinate grid showing a 72-degree angle on the right and its reflection across the y-axis on the left.$

Angle $GHI$ measures $72\degree$ . It is reflected across the y-axis by the rule $(x, y) \rightarrow (-x, y)$ . The image angle opens in the opposite direction. What is the measure of the image angle, in degrees?