Answer:
y = 10
Explanation:
It is given that the 2 triangles are similar,
hence we can write the following relationship based on the length of each side.
3/(3+6) = x / (x+y)
3/9 = x / (x+y)
1/3 = x / (x+y)
(x+y) = 3x -----------(1)
By observing the hypotenuse of both triangles, we can see that
(x + y) = 15 -----------(2)
we can substitute this into equation (1) above to get:
15 = 3x
x = 15/3 = 5 (substitute this back into eq (2) to find y)
(x + y) = 15
(5+y) = 15
y = 15-5
y = 10