Answer:
see explanation
Step-by-step explanation:
Let ∠4 be x then ∠6 is x
∠4 and ∠6 are same side interior angles and are supplementary, thus
x + x = 180
Multiply through by 8 to clear the fraction
8x + x = 1440, that is
9x = 1440 ( divide both sides by 9 )
x = 160
Hence ∠4 = 160° and ∠6 = 160° ÷ 8 = 20°