Calculate angles.
Work out the sizes of the unknown angles.

🙂 = Correct, ☹️ = Incorrect

📌 Rules

• Angles on a straight line add up to 180°: To find a missing angle on a straight line, add the known angles together and subtract the total from 180° (e.g. 180° – 115° = 65°).

• Angles around a point (full turn) add up to 360°: To find a missing angle around a point or inside a circle, add the known angles together and subtract the total from 360° (e.g. 360° – 240° = 120°).

• Angles in a right angle add up to 90°: Look for the square right-angle symbol (∟). Subtract known angles from 90° to find the missing part (e.g. 90° – 35° = 55°).

💡 Tips

• Combine known sections first: When an angle is split into multiple parts, add all the given smaller angles together first before subtracting from 90°, 180°, or 360°.

• Check vertically opposite angles: Where two straight lines cross, opposite angles are equal (e.g. if one angle is 45°, the angle directly opposite is also 45°).

• Quick typing on our platform: Typing your answer is designed to be super quick and simple! Just type plain numbers like 65, 120, or 55 without adding the degree symbol (°), letters, or spaces.

⚠️ Warnings

• Do not use a protractor unless instructed: Diagrams are rarely drawn to scale in tests! Always use angle facts and calculation rather than measuring.

• Don’t forget the square marker means 90°: If a section has a square symbol (∟) instead of a curved arc, it is worth 90° even if the number isn’t written out!