Answer: 52.5 (choice A)
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Explanation:
Take close notice of how the angle markers are drawn.
The angles marked with a single curve or arc pair up together and are congruent. In the triangle on the left, the side 16 is opposite this angle. The triangle on the right has 42 opposite this angle.
So we can form the fraction 16/42 which will help form the proportion later.
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Now focus on the double arc markings. The triangle on the left has side 20 opposite the double arcs. The triangle on the right has the side x opposite the double arcs.
This forms the fraction 20/x
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Set the two fractions we found equal to one another. Isolate x.
16/42 = 20/x
16x = 42*20
16x = 840
x = 840/16
x = 52.5
Side note: other set up equations can be done.
