options: Prove theorems about triangles. Theorems include: a line parallel to one side of a triangle divides the other two proportionally, and conversely; the Pythagorean Theorem proved using triangle similarity.

Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures.
problem_activity: Task
Is the quadrilateral with vertices  $(-6, 2)$, $(-3,6)$, $(9, -3)$, $(6,-7)$
a rectangle? Explain.


correct_option_index: 1