Angles on a line or at a point

Angles on a straight line add to 180°. Angles around a point add to 360°. Enter the angles you know and the working finds the missing one. These are the reasons used for angles in parallel lines. For a triangle, use angles in a triangle.

The red mark is the missing angle on the straight line. The picture is not drawn to the size of your angles.

Where are the angles?

Angle A, in degrees

Angle B, in degrees

Angle C, in degrees

Enter one, two or three angles. Each angle must leave a positive missing angle. On a straight line, every angle is less than 180°. Around a point, every angle is less than 360°.

Guided practice — answer a question at each step before the working is revealed (like the simultaneous equations solver).