Answer:
x = 12
Step-by-step explanation:
For the middle size triangle
short leg = x
long leg = (25 - 9) = 16
ratio = x/16
For the small triangle
short leg = 9
long leg = x
ratio = 9/x
Similar triangles are proportional so
Set the ratios equal
x/16 = 9/x
Cross multiply
x² = 144
Take the square root of both sides
x = 12
