Took me a minute to think.
Form ratios.
x, the small triangle, forms a ratio with 6, the big triangle.
The part of the side that is equal(with the dash) that is part of the small triangle is equal to 6-x, the big triangle.
Yes, you can cross-multiply here!
[tex] \frac{6}{x} = \frac{8}{6-x} [/tex]
Now, cross multiply.
P.S. Use distributive property.
36-6x = 8x
Add 6x on both sides.
36=14x
Divide by 14 on both sides.
x = [tex] \frac{36}{14} [/tex] = [tex] \frac{18}{7} [/tex]
