Question

Trapezoid ABCD is isosceles, with AB = CD. If m∠DAB = 80°, what is m∠BCD?

a.80°
b.100°
c.115°
d.125°

Answer 1

Answer: 100

Step-by-step explanation:m∠DAB = m∠CDA = 80°

The sum of the angles in a quadrilateral is 360°. This gives the equation:

m∠DAB + m∠ABC + m∠BCD + m∠ = 360°

→ 80° + m∠ABC + m∠BCD + 80° = 360°

→ m∠ABC + m∠BCD = 360° - 80° - 80° = 200°

&rarr 2 x m∠BCD = 200°

→m∠BCD = 100°

Answer 2

100 is the answer to this problem