Question

The circle below is centered at the point (4,3) and has a radius length 5. What is its equation

Answer 1

Well, equation of circle is (X-X1)^2 + (Y-Y1)^2 = R^2

so, (X-4)^2 + (Y-3)^2 = 25

X^2 + 16 -8X + Y^2 + 9 - 6Y = 25

X^2 + Y^2  - 8X - 6Y = 0

hope it helped :)

Answer 2

The equation of a circle centred at point (m,n) and radius r is given by

(x-m)² + (y-n)² = r²
-------------------------------------------------------------
Centre = (4,3)
radius = 5

Equation:
(x - 4)² + (y - 3)² = 5²
⇒ x² - 8x + 16 + y² - 6y + 9 = 25
⇒ x² + y² - 8x - 6y + 25 = 25
⇒ x² + y² - 8x - 6y = 0

The equation of the circle is x² + y² - 8x - 6y = 0

Hope it helps!