Question

When the sun is at an elevation of ${40}^{\circ },$ the shadow of a flag post in 15 m. The length of the shadow when sun is at an elevation of ${45}^{\circ }$ will be $[Tan{40}^{\circ }=0.84,Tan{45}^{\circ }=1]$

• A. 13.6 cm
• B. 12.6 cm
• C. 11.6 cm
• D. 14.6 cm

Answer 1

The correct option is B

12.6 cm

Let CB be the flag post. When angle A is ${40}^{\circ },$ length of the shadow is AB

In $\Delta ABC$

$Tan{40}^{\circ }=\frac{H}{15}$

$H=15Tan{40}^{\circ }=12.6cm$

Length of shadow when sun is at an elevation of ${45}^{\circ }=DB$

In $\Delta BDC$

$Tan{45}^{\circ }=\frac{H}{DB}=1$

$H=DB=12.6cm$ is the length of the shadow