Angles
The angles in a triangle always add up to 180°, and in a polygon the sum depends on the number of corners. Try it yourself.
Your numbers
Answer
Angle C
70°
The triangle is acute.
How to work it out
- 1A + B + C = 180°
- 2C = 180° − 50° − 60° = 70°
The formula
A + B + C = 180°
The angles in a triangle always add up to 180°.
(n − 2) · 180°
The angle sum of a polygon with n corners — it can be split into n − 2 triangles.
360° / n
The exterior angle of a regular polygon.
More: Geometry
- PythagorasFind the missing side of a right triangle — with a drawing and working.
- Area and perimeterRectangle, triangle, parallelogram, trapezoid and circle — area and perimeter.
- Volume and surface areaBox, cube, cylinder, cone, sphere and pyramid — also in litres.
- The circleRadius, diameter, circumference and area from one known measurement — and sectors.
- Right triangleSine, cosine and tangent: all sides and angles from two known values.
- Points in the coordinate systemDistance, midpoint and the line between two points — drawn in.