Question 1: The answer is D, vertical angles. Vertical angles means that 2 angles are opposite from each other for 2 lines overlapping each other. The value of those 2 angles should be same.
Question 2: If 2 lines are Perpendicular to each other, their angle should add up to 90°(i.e. Right angle) So, this means that angle ABC and angle CBD should add up to 90°. Before finding the value of angle CBD, we have to find the value of x. 4x = 90° - 30° 4x = 60° X = 15° Therefore, just substitute x = 15° into angle CBD. Angle CBD = 4 x 15° =60°
