Question

Are <OBC and <OB'C' right triangles? How do you know?​

Answer 1

Answer: Yes they are right triangles

Explanation:

The square grid markers help us line up the angles to see that angle OBC is a 90 degree angle, and so is angle OB'C'. Any time a vertical and horizontal line meet up is when you have a 90 degree angle. A right triangle is one where it has a 90 degree angle (aka a right angle).

Extra info: it can be shown that triangle OBC is similar to triangle OB'C', which leads to the fact that the triangles are proportional.