Higher November 2018 Paper 1 Q12
12
\(A\), \(B\) and \(C\) are points on the circumference of a circle, centre \(O\).
\(DAE\) is the tangent to the circle at \(A\).
Angle \(BAE = 56^\circ\)
Angle \(CBO = 35^\circ\)
Work out the size of angle \(CAO\).
You must show all your working. (3)
| Answer | Mark | Mark scheme |
|---|---|---|
| 21 | C1 | for angle \(OAB = 90 - 56\ (= 34)\) |
| C1 | for process to find angle \(CAD\ (= 69)\) or angle \(BCA\ (= 56)\) or angle \(COA\ (= 138)\), eg use of alternate segment theorem or angle at centre is twice the angle at the circumference | |
| C1 | cao |
Additional guidance
Throughout, angles may be written on the diagram; accept as evidence if correct. Ignore absence of degree sign
Reasons need not be given.