Question

Find the radius of the circle if the center is at (1, 2) and the point (-3, 4) lies on the circle.

Answer 1

Answer:

4.47

Step-by-step explanation:

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Answer 2

Answer:

2√5

Step-by-step explanation:

The radius is the distance from the center to a point anywhere along the edge of the circle. To find the distance between these two points, use the distance formula.

$d = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2} \\d = \sqrt{(1--3)^2 + (2-4)^2}\\ d = \sqrt{4^2 + -2^2}\\ d = \sqrt{16 + 4}\\ d = \sqrt{20} \\d = 2\sqrt{5}$