Higher November 2021 Paper 5 Q18
18 A, B, C and D are points on the circumference of a circle.
EF is the tangent to the circle at D.
Angle BDF = 70°.
Not to scale
The ratio angle BCD : angle CBD is 5 : 2.
Work out angle CBD.
You must show your working. [5]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 44 with correct working | 5 | For full marks “correct working” requires evidence of at least M1 AND M1 ie at least a correct angle and some ratio work | |
| B3 for angle BCD = 110 with correct working or M1 for angle BAD = 70 or for angle BDE = 180 – 70 or 110 M1 for angle BCD = 180 – their angle BAD | For B3 “correct working” requires at least M1 or alternate convincing approach Angles may be indicated on diagram for part marks | ||
| AND M2 for their angle BCD ÷ 5 × 2 oe or M1 for their angle BCD ÷ 5 oe If 0 scored SC2 for answer 44 or SC1 for angle BCD = 110 | May be seen on diagram | ||