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 A quadrilateral has angles 90°, 90° and 100°. Find the fourth, in degrees.
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360 − 90 − 90 − 100 = 80°.
2 How many equal sides does a rhombus have?
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Four. All four sides of a rhombus are equal.
3 How many pairs of parallel sides does a trapezium have?
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One pair.
Level 2 · Core
4 A parallelogram has one angle of 75°. Find the adjacent angle, in degrees.
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180 − 75 = 105°.
5 A parallelogram has one angle of 110°. Find the OPPOSITE angle, in degrees.
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110°. Opposite angles of a parallelogram are equal.
6 Which shape has diagonals that are equal AND bisect each other at right angles?
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A square — it is both a rectangle and a rhombus.
Level 3 · Challenge
7 A parallelogram has adjacent angles 4x and 5x. Find x, in degrees.
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9x = 180 → x = 20°. The angles are 80, 100, 80, 100.
8 A quadrilateral has angles x, x, 2x and 2x. Find x, in degrees.
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6x = 360 → x = 60°. The angles are 60, 60, 120, 120.
9 A shape has four equal sides but no right angles. Name it.
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A rhombus. With right angles it would be a square.