Consider a cubical hall A B C D P Q R S with each side 20 m and base as A B C D . If G is the center of the wall B C R Q and T is the midpoint of the side A B , then the angle of elevation of G at the point T is

Step-by-step solution

Let H be the midpoint of B C Since ∠ T B H = 90 o , ⇒ T H 2 = B T 2 + B H 2 = 10 2 + 10 2 = 200 Also, since ∠ T H G = 90 o , ⇒ T G 2 = T H 2 + G H 2 = 200 + 100 = 300 Let θ be the required angle of elevation of G at T . Then, sin ⁡ θ = G H T G = 10 10 3 = 1 3 ⇒ θ = sin - 1 ⁡ 1 3