The angle of elevation of the sun, when the length of the shadow of a tree is equal to the height of the tree, is:
A
30°
B
60°
C
45°
D
None of these
Correct Answer: 45°
Consider the diagram shown above where QR represents the tree and PQ represents its shadow
$$\eqalign{ & {\text{We}}\,{\text{have}},\,QR = PQ \cr & {\text{Let}}\,\angle QPR = \theta \cr} $$
$$\tan \theta = \frac{{QR}}{{PQ}} = 1$$ (since QR = PQ)
$$ \Rightarrow \theta = {45^ \circ }$$
i.e., required angle of elevation = 45°
