Respuesta :

hcheek16

Step-by-step explanation:

A^2 + B^2 = C^2

A and B are the legs of the triangles.

C is the hypotenuse.

12^2 + x^2 = 20^2

144 + x^2 = 400

-144            -144

x^2 = 256

x = 16

The length of the second leg is 16.