The angle of elevation of a building from a measuring instrument placed on the ground is 30°. If the building is 40m high, how far is the instrument from the foot of the building?
\(\frac{20}{√3}\)m
\(\frac{40}{√3}\)m
20√3m
40√3m
Correct answer is D
\(\frac{40}{x}\) = tan 30°
x = \(\frac{40}{tan 30}\)
= \(\frac{40}{1\sqrt{3}}\)
= 40√3m