#8 and #9 I don’t get these the teacher gave us some hard problems

Problem 8
x = distance from the peak of the swingset down to where the support bar is (distance is along the diagonal leg itself)
We have two similar triangles, so we can set up a proportion to solve for x
86/x = 58/28
86*28 = x*58 ... cross multiply
2408 = 58x
58x = 2408
x = 2408/58 ... divide both sides by 58
x = 41.5172413793103
x = 42
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Problem 9
The height is h = 10
The two diameters are 6 and 10, which cut in half to 3 and 5. They are the two radius values (r1 and r2).
Use your calculator to find the following
A = pi*(r1+r2)*sqrt(h^2+(r1-r2)^2)
A = pi*(3+5)*sqrt(10^2+(3-5)^2)
A = 256.304675910626
A = 256.3