Do you think there’s a triangle whose angles measure 41, 76 and 63 degrees? At first, answering this may seem easy. From geometry class we know that the sum of the measures of the interior angles of a ...

The Mathematical Gazette is the original journal of the Mathematical Association and it is now over a century old. Its readership is a mixture of school teachers, college and university lecturers, ...

In this triangle \(a^2 = b^2 + c^2\) and angle \(A\) is a right angle. Pythagoras' theorem only works for right-angled triangles, so you can use it to test whether a triangle has a right angle or not.

Summary We prove the next generalization of the Steiner-Lehmus theorem: if two equal cevians intersect with each other on the angle bisector of the third triangle vertex, then the triangle is ...

The Pythagorean theorem, a cornerstone of mathematics for millennia, provides a method for determining unknown sides in right-angled triangles using the formula a² + b² = c². Its applications extend ...

It is important to remember other angles rules, such as angles on a straight line add up to 180°, and to recognise angles in parallel lines. Make sure you are confident in applying Pythagoras’ theorem ...