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We are given that BA is perpendicular to BD, so that must mean that m∠ABD is a right angle, or 90º. This means: (8x - 10) + (4x + 52) = 90º, since both of the angles add up to become a right angle. We have to solve for x in order to find m∠CBD.
PART 1
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Equation: (8x - 10) + (4x + 52) = 90
Let's add the like values together first.


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Let's subtract 42 from both sides of the equation to isolate the variable we are solving for, x. Our goal is to isolate it completely to get a value that is equal to x.

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Divide both sides by 12 to get our final answer for x.

PART 2
Now that we have x, we simply plug it into our equation for m∠CBD.
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
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Multiply 4 and add 52.

