Right triangle means one angle is 90 degrees. The other two angles add up to 90 degrees. Using light from the sun (to create a shadow) or by using a laser to connect to points of a triangle, we can create a known angles (measure with a protractor). If we can measure one side (distance between two points), we can solve for all angles and sides. Triangles have 3 angles adding up to 180 degrees. Use the Side-Angle-Side Theorem to solve for the side you’d like. We don’t need a right triangle to solve this type of problem. It just saves us from measuring a second angle. Hope this helps.