I disagree with the supplied answer to this question, what do you think? Supplied answer and mine to follow.
Divide it into shapes The central rectangle is 7 x 4 = 28 The 2 triangles are 2 x 4 / 2 = 4 each 28 + 4 + 4 = 36
I realised earlier, I'd got the sums right but I'd misinterpreted the coordinates, I had it as 5 high 12 wide...