Question

Find angle BDC shown in the figure below.

(a) 30

(b) 65

(c) 60

(d) 45

This question was addressed to me at a job interview.

My question is taken from Geometrical Construction topic in division Lettering Practice, Scales & Curves of Civil Engineering Drawing

Answer 1

Correct option is (d) 45

Easiest explanation: Given both the perpendiculars are equal so according to postulate, equal side has equal angle opposite to it.

So, angle ADB = angle BDC, on equating both angles as 7x+17 = 3(4x – 1)                                                                                x=4, and angle BDC = 45.