4MA0 Higher January 2014 Paper 4 Q12

12

Diagram NOT accurately drawn

The diagram shows an equilateral triangle \(ABC\) and an isosceles triangle \(BCD\).
\(AB = AC = BC = CD\).
Angle \(ABD = x^\circ\)

Express the size of angle \(ACD\) in terms of \(x^\circ\), giving your answer as simply as possible.
Give a reason for each step in your working.

(4)