Answer:
∠ ADC = 160°
Step-by-step explanation:
let ∠ CDB = n then ∠ ADC = 8n
The 2 angles are adjacent and lie on a straight line and sum to 180° , then
n + 8n = 180, that is
9n = 180 ( divide both sides by 9 )
n = 20
Then
∠ ADC = 8n = 8 × 20 = 160°
