Basic Rules

If you can learn the following rules then you’re life is going to a lot easier….well….at least during your maths exam.

Angles In A Triangle Add Up To 180°angles in a triangleSo angles A + B + C = 180°

The Exterior Angle Of A Triangle Equals The Sum Of The Opposite Interior Anglesexterior angleSo angle D = A + C

Angles On A Straight Line Add Up To 180°angles on a straight lineSo A + B + C = 180°

Angles In a Quadrilateral (4 Sided Shape) Add Up To 360°angles in a quadSo here x must be 100°

Angles Around A Point Ad Up To 360°angles around a point

So a + b + c = 360°

Isosceles Triangles Have 2 Sides And 2 Angles The Sameisosceles triangleThe two dashes show the two sides are the same length.

The angles marked are the same.