Answer:
13
Step-by-step explanation:
Since the angles form 180 degrees, it will be what the equation is equal to.
Make the equation:
8r + 5 + 5r + 6 = 180
Combine like terms:
8r + 5 + 5r + 6 = 180
13r + 5 + 6 = 180
13r + 11 = 180
Solve:
13r + 11 = 180
-11 -11
---------------------
13r = 169
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13 13
r = 13
Hope this helped.
