Question

Find the radius of the circle whose equation is 3x² + 3y² = 75.

Answer 1

3x² + 3y² = 75
divide everything by 3
x² + y² = 25

This is a standard equation of a circle.
Center (0,0) and radius = 5

Answer 2

Answer: 5 units

Explanation:

We know that the general equation of a circle having center at (h,k) and radius r is given by :-

`(x-h)^2+(y-k)^2=r^2`

Given : The equation of a circle :
`3x^2 + 3y^2 = 75`

Taking 3 as common from the left side of the given equation , we get

`3(x^2 + y^2) = 75`

Divide 3 on both the sides , we get

`x^2 + y^2 = 25`

Comparing to the general equation of circle , we get

`r^2 = 25\\\\\Rightarrow\ r=5`

Hence, the radius of the circle = 5 units