Using the pythagorean theorem, which of the triangles shown are right triangles?

In a school 2/3 of the students study a language of those who study a language 2/5 study french

What point is the projection of q on a) r b) s c) t

One side of a rectangle is 7 feet shorter than seven times the other side. find the length of the shorter side if we also know that the perimeter of the rectangle is 306 feet.