find the equation of the circle with centre (-2,4)and radius 5
Answers
Answer:
Equation of the circle (x + 2)² + (y - 4)² = 25 or x² + y² + 4x - 8y = 5
Given problem:
find the equation of the circle with center (-2,4)and radius 5
Step-by-step explanation:
given center (h, k) = (-2, 4)
given radius (r) = 5 units
the equation of a circle with center (h,k) and radius r = (x-h)²+(y-k)² = r²
the equation of the circle with center (-2, 4) and radius 5
[x -(-2)]² + [y - 4]² = 5²
(x + 2)² + (y - 4)² = 25
[ from (a+b)² = a² +b² +2ab and (a-b)² = a²+b²- 2ab ]
x² + 2² + 4x + y² + 4² - 8y = 25
x² + 4 + 4x + y² + 16 - 8y = 25
x² + y² +4x - 8y + 20 = 25
x² + y² +4x - 8y = 5