Answer:
280°
Step-by-step explanation:
∠2 and ∠5 are the vertex angles. m∠2 = m∠5.
The same
∠1 and ∠6.
m∠1 + m∠2 + m∠5 + m∠6 = 360°
Substitute m∠2 = m∠5 = 40° and m∠1 = m∠6 = x:
x + 40° + 40° + x = 360°
2x + 80° = 360° /subtract 80° from both sides
2x = 280° /divide both sides by 2
x = 140°
m∠1 + m∠6 = x + x = 2x
2x = 228°
