Answer:
A) 68
Step-by-step explanation:
Use the <em>Exterior Angle Theorem</em>.
The Exterior Angle theorem states that the exterior angle's measurement will be equal that of the two opposite interior angles.
Set the equation. Note that you are given the exterior angle and one interior angle:
58 + x = 126
Isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Subtract 58 from both sides of the equation:
x + 58 (-58) = 126 (-58)
x = 126 - 58
x = 68
A) 68 is your answer.
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