Answer:
a = 108°
b = 72°
c = 48°
d = 48°
Explanation:
• ∠a and the 72° angle are on a straight line. Therefore they add up to 180°:
∠a + 72° = 180°
⇒ ∠a = 180 - 72°
⇒ ∠a = 108°
• ∠b and the 72° angle are corresponding angles (the angles make an F-shape). Therefore, they are equal:
∠b = 72°
• ∠d and the 48° angle are alternate angles (the angles make a z-shape). Therefore they are equal:
∠d = 48°
• ∠c and ∠d are vertically opposite angles. Therefore, they are equal:
∠c = ∠d
⇒ ∠c = 48°