# maths

given the following equation for a circle x^2-8x+y^2+4y+11=0 find its centre and radius

1. 👍
2. 👎
3. 👁
1. x^2-8x+y^2+4y+11=0

by completing the square...

x^2-8x+ 16 +y^2+4y+ 4 = -11 + 16 + 4

(x-4)^2 + (y+2)^2 = 9

I am sure you can take it from here

1. 👍
2. 👎

## Similar Questions

1. ### maths

calculate the area of a sector of a circle which subtends an angle of 45° at the centre of the circle, radius 14cm

2. ### Math

(b) what angle does an arc 5.5cm in length subtends at the centre of length subtend at the centre of a circle of radius 1/2m?

3. ### NEED MAJOR HELP! *QUADRATIC EQUATIONS*

Write the equation for the circle with center at (- 8, - 6) and radius of 10. (x+8)² + (y + 6)² = 10 (x+8)² + (y + 6)² = 100 (x-8)² + (y - 6)² = 100 Find the standard equation for the circle with center on the positive

4. ### Physics

Which of the following is the equation of the circle with centre (-1.5, 0.5) and radius 3? A. 2x^2 + 6x + 2y^2 - 2y - 13 = 0 B. 2x^2 - 6x + 2y^2 + 2y - 13 = 0 C. 2x^2 - 6x + 2y^2 - 2y - 13 = 0 D. 2x^2 + 6x + 2y^2 - 2y - 23 = 0 E.

1. ### math

A sector of a circle subtending an angle 300 degrees at the centre is used to form a cone with base radius 6cm. Find the (a.)radius of the circle (b.)volume of the cone (c.)area of the minor sector of the circle

2. ### Math

The adjoining circle with centre o has radius of 14 cm .ABCD is a square drawn inside the circle calculate the area of the shaded region.

3. ### GEOMETRY

The diameter of a circle has endpoints P(–10, –2) and Q(4, 6). a.Find the center of the circle. b.Find the radius. If your answer is not an integer, express it in radical form. c.Write an equation for the circle.

4. ### mathematics

A chord of a circle is 9cm. If its distance from the centre of the circle is 5cm,calculate the radius of the circle

1. ### math

Let the equation of a circle be x^2+y^2-14x+8y+56 a. Find the standard form of the circle b. Find the center of the circle c. Find the radius of the circle

2. ### Maths

A sector of a circle of radius 7cm subtending an angle of 270 degree at centre of the circle is use to form a cone? (A)find the base radius of the cone. (B)calculate the area of the base of the cone.

3. ### math

in a circle of radius 6cm , a chord is drawn 3cm from the circle (a)calculate the angle subtended by the chord at the centre of the circle

4. ### coordinate geometry

find the equation of circle having centre in 1st quadrant, touching x-axis,having a common tangent y=3^1/2x+4 with the circle x^2+y^2+4x+4y+4=0 such that the distance between two circles along the x-axis is 3 units ?