The equation of a circle with centre (x0, y0) and radius r is given by:
(x - x0)² + (y - y0)² = r²
The circle with centre (3, -5) and passing through the point (6, -7) has radius:
use Pythagoras:
radius = distance from centre (x0, y0) to point (x1, y1) = √((x1 - x0)² + (y1 - y0)²)
→ radius = √((6 - 3)² + (-7 - -5)²) = √(3² + (-2)²) = √(9 + 4) = √13
Thus the equation is:
(x - 3)² + (y - -5)² = (√13)²
→ (x - 3)² + (y + 5)² = 13
Which can be expanded to give:
x² - 6x + 9 + y² +10y + 25 = 13
→ x² - 6x + y² + 10y + 21 = 0
It works out that the circle's centre is at (3, -2) and its radius is 5 on the Cartesian plane.
The chord that passes through the centre is the biggest chord in a circle and it is the diameter.
The equation works out as: (x-1)2+(y+0.5)2 = 18.25 Equation of a circle: (x-a)2+(y-b)2 = radius2 whereas a and b are the coordinates of the circle's centre
x2 + y2 = 25 A circle with centre (xo, yo) and radius r has equation: (x - xo)2 + (y - yo)2 = r2 So with centre the origin (0, 0) and radius 5 cm, the circle has equation: (x - 0)2 + (y - 0)2 = 52 ⇒ x2 + y2 = 25
Diameter end points: (2, -3) and (8, 7) Centre of circle: (5, 2) Length of diameter: 2 times square root of 34 Equation: (x-5)^2+(y-2)^2 = 34 which in effect is the radius squared Area in square units: 34*pi
Centre of the circle is at (7, 7) and its Cartesian equation is (x-7)^2 + (y-7)^2 = 49
It works out that the circle's centre is at (3, -2) and its radius is 5 on the Cartesian plane.
Centre of the circle: (3, 8) Radius of the circle: 2 Cartesian equation of the circle: (x-3)^2 + (y-8)^2 = 4
The equation of the circle works out as: (x+2)^2 + (y-5)^2 = 41 The circle's centre is at: (-2, 5) Its radius is the square root of 41
Points: (5, 0) and (3, 4) and (-5, 0) Equation works out as: x^2+y^2 = 25 Radius: 5 units in length Centre of circle is at the point of origin (0, 0) on the Cartesian plane.
Centre of circle: (3, -5) Distance from (3, -5) to (6, -7) is the square root of 13 which is the radius Equation of the circle: (x-3)^2 + (y+5)^2 = 13
Using the formula of x^2 +2gx +y^2 +2fy +c = 0 it works out that the centre of the circle is at (6.5, 3) and its radius is 2.5 units in length. Alternatively plot the points on the Cartesian plane to find the centre and radius of the circle.
End points: (10, -4) and (2, 2) Midpoint: (6, -1) which is the centre of the circle Distance from (6, -1) to any of its end points = 5 which is the radius Therefore the Cartesian equation is: (x-6)^2 +(y+1)^2 = 25
Points: (6, 3) (-5, 2) and (7, 2) Circle's equation works out as: (x-1)^2+(y+3)^2 = 61 Centre of the circle is at: (1, -3) Radius of the circle is the square root of 61 which is about 7.81 to two decimal places
It works out that the centre of the circle is at (4, -3) on the Cartesian plane and its area is 56.549 square cm rounded up to three decimal places.
The equation of a circle with centre (x0, y0) and radius r is given by: (x - x0)² + (y - y0)² = r² For the circle with centre (-1, -7) and radius 10 this gives: (x - -1) + (y - -7)² = 10² → (x + 1)² + (y + 7)² = 100 This can be expanded and rearranged to give: x² +2x + y² + 14y - 50 = 0
Endpoints: (10, -4) and (2, 2) Midpoint: (6, -1) which is the centre of the circle Distance from (6, -1) to (10, -4) or (2, 2): 5 which is the radius of the circle Therefore equation of the circle: (x-6)^2 + (y+1)^2 = 25