Answer:
255) 36°
257) 30°
Explanation:
The sum of the angle measures in a triangle is 180°.
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255)
(x +43) +(x +77) +74 = 180
2x = -14 . . . . . . . . . . . subtract 194
x = -7
∠A = -7 +43 = 36°
__
257)
5x +(3x +2) +130 = 180
8x = 48 . . . . . . . . . . . . . . subtract 132
x = 6
∠A = 5·6 = 30°