Step-by-step explanation:
y is the height of the main right-angled triangle.
one of the attributes of such a height from the 90° angle is that it is the square root of the product of the segments it splits the Hypotenuse into.
so, y = sqrt(15×5) = sqrt(75) = sqrt(25×3) = 5×sqrt(3) =
= 8.660254038...
but 5×sqrt(3) is most likely the answer your teacher expects.
and x can now be solved via regular Pythagoras on the smallest triangle :
x² = y² + 5² = 75 + 25 = 100
x = 10
