MENUCircle Theorems
Work out the missing angles. The angles you have to find are the letters printed in blue. Every dot in the middle of a circle is its centre.
These are the rules you need:
- The angle at the centre is twice the angle at the circumference standing on the same arc.
- Angles standing on the same arc, in the same segment, are equal.
- The angle in a semicircle is 90°.
- The opposite angles of a cyclic quadrilateral add up to 180°.
- Two radii make an isosceles triangle, so its two base angles are equal.
Reload the page and you get a new worksheet - the angles are generated at random every time.
