Question 753985
Assuming the 3 lines with the red arrows are parallel:
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That gives 3 similar triangles.
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b/10 = 12.5/(15+10)
b = 5
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a/(5+15+10) = b/10 = 5/10
a = 15
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(12+c)/12.5 = c/b = c/5
12.5c = 5(12+c) = 5c + 60
c = 8
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(d+12+c)/a = c/b
(d+20)/15 = 8/5
5d + 100 = 120
d = 4
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There are other ways to do it.