1 Fisgard Lighthouse in British Columbia is Canada s oldest West Coast lighthouse Riaz needs to know the height of the lighthouse This diagram shows the length of the shadows cast by Riaz and by the lighthouse at the same time 0 1 62 m 32 4 m 3 6 m a The sunlight is hitting the ground at the same angle in both triangles How do you know the triangles are similar b What is the height of the lighthouse to the nearest tenth of a metre