Question

How do you convert the rectangular equation `x^2+y^2=16` into polar form?

Answer 1

`r=4`

Explanation:

Since by the Pythagorean Theorem
`color(white)("XXX")x^2+y^2=r^2`

Note that for the polar form of this equation, the angle, `theta`, is irrelevant (Similar to the case in rectangular form for a vertical line `x=2`, where `y` is irrelevant).