Question

In quadrillateral ABCD,side AB is parallel to side DC.If angle A : angle D=1:2 and angle C:angle B=4:5
calculate each angle

Answer 1

Sin^2 A = 1/2 tan^2A= 1/(2*(1)^2) =1/2, As angle A is an acute angle.

So,

SinA = 1/√2 , You know value of sin 45°=1/√2

Or,

A = Sin^(-1) {1/√2} = 45°

So, A = 45°