Answer:
<h2>a = 11</h2>
Step-by-step explanation:

Supplementary angles add up to 180º
If one is 40º, then the other is (180º-40º) = 140º
None of those choices describes a plane.
choice C is the only example of a plane.
Pretty sure it would be 21x^2+16x+17y
1:Replace the variables in the theorem with the values of the known sides.
2:Square the measures, and subtract from each side
3: find the square root of each side
Answer:
Step-by-step explanation: