Question

What is the radius for the circle given by the equation x^2+(y-3)^2=21

Round your answer to the nearest thousanth.

Answer 1

x² + (y - 3)² = 21

We know the formula is (x - xo)² + (y - yo)² = r²

So, 21 is the radius²

21 = r²

r = √21

r = 4,58257

Rounding

r = 4,583

Answer 2

4.583

Explanation:

Equation of a circle is:

(x − h)² + (y − k)² = r²

where (h, k) is the center of the circle and r is the radius.

x² + (y − 3)² = 21

The center of the circle is (0, 3), and the radius is √21, or approximately 4.583.