The sum of all five angles is 540 degrees.
A) 4*congruent angles + 5th angle = 540
B) (5th angle) -30 = 2*cong angle
A) 5th angle = 540 -4*cong angle
B) 5th angle = 2*(cong angle) -30
Multiplying B) by -1
B) -5th angle = -2*(cong angle) +30 then adding to A)
A) 5th angle = 540 -4*cong angle
-2*(cong angle) +30 = 540 -4*cong angle
2*(cong angle) = 510
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By trial and error I determined
each congruent angle = 95
5th angle = 160