Answer:
10
Step-by-step explanation:
There's probably a lot of ways you could solve this. I think what I would do is find the top angle of the big triangle first because it will be the same as the angle accross from it in the little triangle. We'll call this angle X1 for the big triangle and X2 for the little triangle.
X1 = X2
TAN(X1) = opposite/adjacent
TAN(X1) = 50/40
X1 = CoTAN(50/40)
X1 = 51.34 = X2
TAN(X2) = d/8
TAN(51.34) = d/8
d = TAN(51.34) * 8
d = 10
If you're unfamiliar with trig functions you could also use a proportion.
[tex]\frac{50}{40} =\frac{d}{8}[/tex]
cross multiply to get
400 = d*40
divide by 40
d = 10
Now that I look at it, that's probably the way they want you to do it, but as you see, it works either way!
