4400 Higher November 2004 Paper 3 Q12
12 \(A\), \(B\), \(C\) and \(D\) are points on a circle.
Angle \(BAC = 40^\circ\).
Angle \(DBC = 55^\circ\).

Diagram NOT accurately drawn
(a)
(i) Find the size of angle \(DAC\).
(ii) Give a reason for your answer. (2)
(b)
(i) Calculate the size of angle \(DCB\).
(ii) Give reasons for your answer. (3)
(c) Is \(BD\) a diameter of the circle?
Give a reason for your answer. (1)
Give a reason for your answer. (1)
| Scheme | Marks |
|---|---|
| (i) Answer: 55° | B1 |
| (ii) ∠s in same seg | B1 |
| (2) |
Notes
B1: or equiv, eg both stand on \(DC\)
| Scheme | Marks |
|---|---|
| (i) Answer: 85° | B1 |
| (ii) Opp ∠s of cyc quad | B1 |
| 180 − (40 + 55) | B1 |
| (3) |
Notes
B1: or \(BDC = 40\), ∠s in same seg
| Scheme | Marks |
|---|---|
| No. \(DCB\) (or \(DAC\)) \(\neq 90^\circ\) | B1 |
| (1) | |
| (6 marks) |