Work through the levels in order. Type your answer and press Check — open the worked solution if you get stuck. Answers like -6, 3/4 or 0.25 are typed exactly as shown.
Level 1 · Warm-up
1 Two angles sit on a straight line. One is 70°. Find the other, in degrees.
Show worked solution
180 − 70 = 110° (angles on a straight line).
2 Two lines cross; one angle is 45°. Find the vertically opposite angle, in degrees.
Show worked solution
45° (vertically opposite angles are equal).
3 What does a small square drawn in a corner of a diagram mean?
Show worked solution
A right angle — exactly 90°.
Level 2 · Core
4 A transversal crosses parallel lines. An alternate angle pair has one angle of 82°. Find the other, in degrees.
Show worked solution
82° (alternate angles, the lines are parallel).
5 Three angles meet at a point. Two are 130° and 90°. Find the third, in degrees.
Show worked solution
360 − 130 − 90 = 140° (angles at a point).
6 An isosceles triangle has an apex angle of 30°. Find a base angle, in degrees.
Show worked solution
2x = 150 → x = 75° (base angles of an isosceles triangle).
Level 3 · Challenge
7 A transversal crosses parallel lines. One angle is 68°. Find the CO-INTERIOR angle, in degrees.
Show worked solution
180 − 68 = 112° (co-interior angles, parallel lines).
8 A triangle has angles 2x, 3x and 4x. Find the largest angle, in degrees.
Show worked solution
9x = 180 → x = 20. The angles are 40, 60 and 80°.
9 In a quadrilateral, three angles are 95°, 85° and 100°. Find the fourth, in degrees.
Show worked solution
360 − 95 − 85 − 100 = 80° (angle sum of a quadrilateral).