Final answer:
To find the value of x for the vertical angles, set the two expressions (6x + 21) and (5x + 25) equal to each other since vertical angles are congruent. After solving the equation, we determine that x equals 4.
Step-by-step explanation:
The question requires us to find the value of x given two expressions for the measures of vertical angles, which are equal. We have m21 = (6x + 21)° and m/2 = (5x+ 25)°. Since vertical angles are congruent, we can set these two expressions equal to each other and solve for x.
Setting the two expressions equal, we get:
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- (6x + 21) = (5x + 25)
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- 6x - 5x = 25 - 21
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- x = 4
The value of x that satisfies the equation is 4. Therefore, the measures of the angles can also be calculated by substituting x back into the expressions.