For two right-angled triangles, if an angle (other than the right angle) is the same, the third angle will also be the same. This is true because angles in a triangle add up to 180°.

Slide 1 of 6, Example one. An image of a right angled triangle. The right angle is the bottom left vertex of the triangle. The bottom right vertex has been labelled theta. A diagonal arrow points ...

Each triple is the lengths of the three sides of a right-angled triangle, where each side is a whole number. The simplest example is (3, 4, 5); others include (5, 12, 13) and (8, 15, 17).