When the shadow cast by a 1.2 m fence post was 1.8mthe shadow cast by a pine tree was 27.6m and by an oak tree was 45m.How tall was each tree?

Answer 1

There are similar triangles with the shadows as one side, the objects as another and the sun's rays as the third.

The ratio of height to shadow is 1.2m : 1.8m = 1.2 : 1.8 = 2 : 3

Therefore to convert shadow length to height divide by 3 and multiply by 2, which is the same as multiplying by 2/3

→ height pine = 2/3 × 27.6 m = 18.4 m

→ height oak = 2/3 × 45 m = 30 m

Answer 2

The pine was 18.4 m and the oak was 30 m.