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

4.47

Step-by-step explanation:

2
`√(5)`=4.47

Answer 2

The radius of the circle is
`2√(5)` units.

Step-by-step explanation:

Given information: (1,2) is center of the circle and the point (-3, 4) lies on the circle.

Distance between any point on the circle from the center of the circle is known as radius.

So, radius of the circle is the distance between two points (1,2) and (-3, 4).

Distance formula:

`D=√((x_2-x_1)^2+(y_2-y_1)^2)`

Using distance formula, we get

`r=√((-3-1)^2+(4-2)^2)`

`r=√((-4)^2+(2)^2)`

`r=√(16+4)`

On further simplification, we get

`r=√(20)`

`r=2√(5)`

Therefore the radius of the circle is
`2√(5)` units.