By the definition of a parallelogram, ad∥bc and ab∥dc. using, ad as a transversal, ∠a and ∠ are same-side interior angles, so they are . by the definition of supplementary, m∠a + m∠d = 180. using side as a transversal, ∠b and ∠c are same-side interior angles, so they are supplementary. by the definition of supplementary, m∠b + m∠c = 180. so, m∠a + m∠d + m∠b + m∠c = 180 + 180 by the property. simplifying, we have m∠a + m∠b + m∠c + m∠d = 360˚.

found it xd it ok yt

126 maybe. sorry

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.