Answer:
B a = 180 -77-60
Step-by-step explanation:
The angles add to 180 degrees since they form a straight line
77+ 60+a = 180
a = 180 -77-60
Answer: D. (6, 9)
<u>Step-by-step explanation:</u>
Midpoint is the "average" of the x's and y's:
Given: (5, 13) and (7, 5)
Midpoint: 
= 
= (6, 9)
These angles are adjacent angels.
adjacent angels- have a common side and the same vertex.
(pictured below)
To solve this we set the sum of both angles equal to 180°. We do this because they are two adjacent angles on a straight line. The measure of a straight lines angle is 180°.
180= 5x + (x+96)
180=6x+96
84= 6x
x=14
any questions?