Mathematics

Space and geometry

Test an angle-sum fact (straight line, point, or triangle), a property of a named 2D/3D shape, a symmetry count, or simple coordinate/grid reading.

Angle facts worth memorising

Three facts cover almost every angle question at this level: angles on a straight line add to 180°, angles around a point add to 360°, and the three angles inside any triangle add to 180°. Nearly every "find the missing angle" question is just one of these three facts in disguise.

Worked example: Two angles sit on a straight line. One is 70°. The other is 180° − 70° = 110°.

Shapes and symmetry

A shape has a line of symmetry if you can fold it so both halves match exactly. Regular shapes (all sides and angles equal) have one line of symmetry for every side — a regular pentagon has 5, a regular hexagon has 6.

How to attack this question type

  • 1

    Before calculating, decide WHICH rule applies: straight line (180°), full turn (360°), or triangle (180°). Getting this choice right is most of the question.

  • 2

    To count lines of symmetry, imagine folding the shape in every direction — through opposite corners AND through the midpoints of opposite sides. Both count.

  • 3

    Learn the polygon names by side count: triangle (3), quadrilateral (4), pentagon (5), hexagon (6), octagon (8) — a question naming a shape is testing whether you know this.

  • 4

    On a coordinate grid, the first number always tells you how far ACROSS, and the second how far UP — "along the corridor, then up the stairs."

  • 5

    A right angle is exactly 90°. Acute is smaller than that, obtuse is bigger than 90° but less than 180°, reflex is bigger than 180°.

Practice · untimed

Question 1 of 20 correct so far

Two angles lie on a straight line. One of them is 125°. What is the other angle?

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