Higher November 2020 Paper 3 Q21
21
(a) A and B are points on a circle.
PA and PB are tangents.
Not drawn accurately
Work out the size of angle APB. [2 marks]
(b) C, D and E are points on a different circle.
Not drawn accurately
Is X the centre of the circle?
Tick a box.
- Yes
- No
Show working to support your answer. [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| Angle ABP = 71 or \(180 - 2 \times 71\) or \(180 - 142\) or \((180 - 90 - 71) \times 2\) | M1 | oe may be marked on diagram in correct position |
| 38 | A1 |
Additional guidance
| 71 or 38 in working with either angle correctly identified, 180 on answer line | M1A0 |
| 71 or 38 in working with neither angle correctly identified, 180 on answer line | M0A0 |
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| (Angle CXD =) \(360 - 204\) or 156 | M1 | may be marked on diagram in correct position |
| \(156 \div 2 = 78\) and Yes or \(78 \times 2 = 156\) and Yes | A1 | |
| Alternative method 2 | ||
| (Angle CXD =) \(78 \times 2 = 156\) | M1 | may be marked on diagram in correct position |
| \(204 + 156 = 360\) and Yes or \(360 - 156 = 204\) and Yes | A1 | |
Additional guidance
| Angle CXD should be double angle CED | M0A0 |