Exercises: Prove Theorems About Lines and Angles

Work through each section in order. For proof problems, show each step with its justification. Express angle measures in degrees.

Grade 9·21 problems·~35 min·Common Core Math - HS Geometry·standard·hsg-co-c-9

Work through problems with immediate feedback

Fluency Practice

Apply the theorems directly. Identify angle relationships and find missing measures.

Two lines intersect. One angle at the intersection measures $47^\circ$ . What is the measure of the vertical angle?

$43^\circ$

$133^\circ$

$47^\circ$

$90^\circ$