Answer: D. 10
Explanation:
Concept:
Here, we need to know the triangle sum theorem.
The Triangle Sum Theorem states that the sum of the three interior angles in a triangle is always 180°.
If you are still confused, please refer to the attachment below for a graphical explanation.
Solve:
According to the Triangle Sum Theorem:
∠1 + ∠2 + ∠3 = 180
Substitute the angle values
(60) + (50) + (7x) = 180
Combine like terms
110 + 7x = 180
SUbtract 110 on both sides
110 + 7x - 110 = 180 - 110
7x = 70
Divide 7 on both sides
7x / 7 = 70 / 7
x = 10
Hope this helps!! :)
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