Math 9 · Unit 5: Angles · Cambridge Lower Secondary Maths Stage 9

Questions

1. 1. Work out the lettered exterior angles, a in the triangle and b in the quadrilateral.

   • a = 103°, b = 119°
   • a = 57°, b = 109°
   • a = 123°, b = 71°
   • a = 123°, b = 109°
   Check

2. 2. What is the exterior angle of a square?

   • 45°
   • 90°
   • 180°
   • 360°
   Check

3. 3. What is the exterior angle of an equilateral triangle?

   • 60°
   • 120°
   • 90°
   • 180°
   Check

4. 4. A parallelogram has an interior angle of 74°. What are its exterior angles?

   • 16° and 164°
   • 74° and 74°
   • 106° and 74°
   • 106° and 106°
   Check

5. 5. A pentagon has exterior angles of 60°, 70°, 80° and 90°, as in the diagram. Work out the value of a.

   • 300
   • 60
   • 120
   • 90
   Check

6. 6. All the exterior angles of a pentagon are equal. What size is each one?

   • 108°
   • 60°
   • 72°
   • 90°
   Check

7. 7. A regular polygon has an exterior angle of 60°. How many sides does it have?

   • 60
   • 8
   • 3
   • 6
   Check

8. 8. A regular polygon has an exterior angle of 45°. How many sides does it have?

   • 9
   • 45
   • 8
   • 6
   Check

9. 9. A regular polygon has an exterior angle of 40°. How many sides does it have?

   • 8
   • 4
   • 10
   • 9
   Check

10. 10. A regular polygon has an exterior angle of 36°. How many sides does it have?

    • 12
    • 36
    • 9
    • 10
    Check

11. 11. Why can't the exterior angle of a regular polygon be 50°?

    • Exterior angles must be even.
    • 360 ÷ 50 is not a whole number.
    • 50° is too big.
    • Exterior angles cannot be more than 45°.
    Check

12. 12. The interior angle of a regular polygon is 170°. What is the exterior angle?

    • 170°
    • 10°
    • 190°
    • 20°
    Check

13. 13. The interior angle of a regular polygon is 170°. How many sides does it have?

    • 36
    • 17
    • 18
    • 10
    Check

14. 14. A square, a regular hexagon and another regular polygon meet at P. Work out the number of sides of the other regular polygon.

    • 6
    • 12
    • 8
    • 10
    Check

15. 15. Two identical regular polygons meet along AB. At A, the gap between them is 20°. How many sides does each polygon have?

    • 9
    • 36
    • 18
    • 20
    Check

16. 16. AB, BC and CD are three sides of a regular polygon. BC is parallel to AD, and AB makes an angle of 30° with AD. How many sides does the polygon have?

    • 30
    • 12
    • 6
    • 10
    Check

17. 17. Three exterior angles of a hexagon are x° and the other three are (x + 10)°. What is x?

    • 65
    • 60
    • 55
    • 50
    Check

18. 18. The exterior angles of an octagon are y°, (y + 2)°, (y + 4)°, (y + 6)°, (y + 8)°, (y + 10)°, (y + 12)° and (y + 14)°. Work out the largest interior angle.

    • 38°
    • 142°
    • 52°
    • 128°
    Check