Know the definition, formula, proof, examples and applications of Pythagoras Theorem. ... ∠C = ∠G (Corresponding angles of congruent triangles) ∠G = 90° (By construction) So ∠C = 90°.

Slide 1 of 9, Example one.A series of three images. Each image shows a right angled triangle. The first triangle has vertices labelled A, B, and C. The right angle is at vertex C.