Question

$\huge {\sf {\underline {\underline {\red {Question :-}}}}}$

The angle of elevation of an aeroplane as observed from a point 10cm above ground is found to be 30° & the angle of depression of the reflection in lake is found to be 60°. Determine the height of the aeroplane from the ground.​

Answer 1

Step-by-step explanation:

( attached image )

Hope it helps you !

Answer 2

Answer

• The height of the aeroplane is 20 cm

Explanation

Given

• Angle of elevation of an aeroplane as observed from a point 10 cm above the ground is 30°
• Angle of depression of the reflection in Lake is 60°
• Height of the aeroplane from the ground

To Find

• Height of the aeroplane

Solution

✭ Consider triangle ABF

→ tanθ = Opposite/Adjacent

→ tan 30° =AB/BF

→ 1/√3 = (h - 10)/BF

→ BF = (h - 10) √3 ❲ eq(1) ❳

✭ Consider triangle BFD

→ tanθ = Opposite/Adjacent

→ tan 60° = BD/BF

→ √3 = h + 10/BF

→ BF = (h + 10)/√3 ❲ eq(2) ❳

From eq(1) and eq(2)

→ h - 10√3 = h + 10/√3

→ h - 10 = (h + 10)/3

→ 3h - 30 = h + 10

→ 2h = 40

→ h = 20 cm