Answer:
y=6
Explanation:
Since this is a rhombus, the 4 triangles must have the same base and height. They are also all right triangles, and we are given the hypotenuse (x+5) and (2x). They each must be equal, so we can form the equation x+5=2x to solve for one of them:x=5. So one of the legs is y, the other is 8, and the hypotenuse is 5+5=10. We can use the pythagorean theorem to solve: y^2+8^2=10^2.
y^2+64=100
y^2=100-64=36.
y=6.