Lesson 12 - Unit 2 - Geometry - Illustrative Mathematics

Lin is using the diagram to prove the statement, “If a parallelogram has one right angle, it is a rectangle.”

Given that EFGH is a parallelogram and angle HEF is right, which reasoning about angles will help her prove that angle FGH is also a right angle?

ABDE is an isosceles trapezoid.

 Select all pairs of congruent triangles.

Match each conjecture with the rephrased statement of proof connected to the diagram.

Which of the following criteria always proves triangles congruent? Select all that apply.

Select all true statements based on the diagram.

Diego states that diagonal WY bisects angles ZWX and ZYX. Is he correct?

Explain your reasoning.

Sketch the unique triangles that can be made with angle measures 80^o and 20^o and side length 5. How do you know you have sketched all possibilities?