Need help with geometry problem

Answer:
y = [tex]6\sqrt{5}[/tex]
Step-by-step explanation:
x^2 + z^2 = 29^2
x^2 = y^2 + 9^2
y^2 + 20^2 = z^2
29^2 - z^2 = y^2 + 81 (equating for x^2 from eqn 1 and 2)
substitute 3rd eqn in 4th
29^2 - (y^2 + 20^2) = y^2 + 81
841 - y^2 - 400 = y^2 + 81
441 = 2y^2 + 81
360 = 2y^2
y^2 = 180
y = [tex]\sqrt{180}[/tex]
= [tex]\sqrt{36*5} \\[/tex]
y = [tex]6\sqrt{5}[/tex]