Foundation June 2018 Paper 2 Q12

12 The diagram shows a quadrilateral \(ABCD\) on a centimetre grid.

Centimetre grid with x from 0 to 6 and y from 0 to 5; A at (1, 1), B at (3, 1), C at (5, 4), D at (2, 4); quadrilateral ABCD with diagonal AC drawn
(a) Work out the area of triangle \(ABC\).
You must include the units with your answer. (3)
(b) Give a reason why angle \(ACD\) is equal to angle \(CAB\). (1)
(c) Write down an equation for the straight line that passes through \(D\) and \(C\). (1)