Amrita stood near the base of a lighthouse, gazing up at its towering height. She measured the angle of elevation to the top and found it to be $60°$. Then, she climbed a nearby observation deck, 40 m

Question

Amrita stood near the base of a lighthouse, gazing up at its towering height. She measured the angle of elevation to the top and found it to be

60°

. Then, she climbed a nearby observation deck, 40 metres higher than her original position and noticed the angle of elevation to the top of lighthouse to be

45°

.

$Lighthouse photo$

$Lighthouse geometry diagram$

(i) If CD is

h

metres, find the distance BD in terms of

h

.

[IMAGE_1]

[IMAGE_2]

(i) If CD is $h$ metres, find the distance BD in terms of $h$.

Accepted Answer

Step 1: $\frac{h}{BD} = 	an 45° = 1 \Rightarrow BD = h$ m

Question

Solution