Question

Find the value of y.

Answer 1

Try this option:
1. the sides of the biggest triangle are 16; x and √(16²-x²); the sides of the smallest triange are x;5 and y. The smallest triangle ~ the biggest triangle. Using the property of the similar triangles: 
$\frac{x}{5} = \frac{16}{x}, \ then \ x= \sqrt{80}$
2. according to the Pyphagorean theorem (in the smallest triangle):
$y= \sqrt{ \sqrt{80^2} -5^2} = \sqrt{55}$

answer: y=√55.