Respuesta :

Hey there! :D

Plug it into the Pythagorean theorem. 

a^2+b^2= c^2

a^2+16^2= 65^2

Square the numbers. 

a^2 + 256= 4225

Subtract 256 on both sides. 

a^2= 3969

Find the square root of 3969. 

a= 63

I hope this helps!
~kaikers