What are the solutions to the equations?
x^2 + y^2 =5
y=2x

X^2+(2x)^2=5
x^2+4x^2-5=0
5x^2-5=0
5(x^2-1)=0
x^2-1=0
(x+ square root of 1)*(x- square root of 1)=0
x= square root of 1 or x= - square root of 1
then plug into y=2x
y= 2 times square root of 1 or y= -2 times square root of 1

We need more info then that

B. 2 1/2 feet. multiply 2.5 inches by 12 to get thirty inches then divide by 12 to get 2.5 feet