General formula to find area of circle could be written as following.
a = π × r²
To find the area, we need to find the value of r²
To find the value of r² we need to use circle equation
General formula to form a circle equation
(x - a)² + (y - b)² = r²
(a,b) is the central point, (x,y) is one of the points in the circle
Plug the numbers into circle equation
Original points equal (0,0), so (0,0) is the central point (a,b)
(x - a)² + (y - b)² = r²
(x - 0)² + (y - 0)² = r²
x² + y² = r²
(3,0) acts as (x,y) because it lies on the circle
x² + y² = r²
3² + 0 = r²
9 = r²
The value of r² equals 9
Input 9 to the area formula
a = π × r²
a = 3.14 × 9
a = 28.26
The area of the circle is 28.26 units²
