Question

If the angles of elevation of the top of lower from three collinear points A, B and C, on a line leading to the foot of the lower, are 30°, 45° and 60° respectively, then the ratio, AB : BC, is

(A) √3:1 

(B) √3: √2 

(C) 1: √3 

(D) 2 : 3

Answer 1

Correct option (A) √3:1

Explanation:

tan30° = h/AD ⇒ AD = h√3

BD = h; CD = h/√3

AB/BC = (AD - BD)/(BD - CD) = (√3 - 1)/(1 - 1/√3) = (3 - √3)/(√3 - 1) = √3