Answer:
∠ CAO = 56°
Explanation:
∠ CAO and ∠ DOA are same- side interior angles and sum to 180° , so
∠ CAO + ∠ DOA = 180 , that is
2x + 3x + 40 = 180
5x + 40 = 180 ( subtract 40 from both sides )
5x = 140 ( divide both sides by 5 )
x = 28
Then
∠ CAO = 2x = 2 × 28 = 56°