4. The diagram shows a structure that is used to support a cable. The support is bolted on to the top of a wall at point F and supports a cable from point H. 100 89 154 65 110 44% b H (a) Calculate the length of side 'a'. Diagram not to scale and all dimensions in mm (b) Calculate the angle 0. (c) Calculate the length of side 'c'. (d) Calculate the height of point 'H' compared to point 'F'.