Use Green's Theorem...
(This One's Different from my last one)

a = √ x^2 + y^2 or a = −√x^2 + y^2

Step-by-step explanation:

Let's solve for a.

x2 + y2 = a2

Step 1: Flip the equation.

a2 = x2 + y2

Step 2: Take square root.

final a = √x2 + y2 or a = −√x2 + y2

a = √x^2 + y^2

        OR

a = − √x^2 + y^2

Step-by-step explanation:

x^2 + y^2 = a^2, which can also be written as:

a^2 = x^2 + y^2

Taking the square root on both sides, we get:

a = √x^2 + y^2

        OR

a = − √x^2 + y^2

Hope this helps!

answer: idk wbu

step-by-step explanation: umm..