SSC CGL 2 Sep 2016 Shif 2 Paper

The angle at the circumference of a semi–circle is a right angle.
∴ ∠BAC = 90°
∠ABC = 36°
∴ ∠ACB = 90° – 36° = 54°
∠BCD = 90°
∴ ∠ACD = 90° – 54° = 36°
∠DAC = 90°
∴ ∠ADC = 90° – 36° = 54°