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
It is: (x-3)2+(y+5)2 = 13
Circle equation: x^2 +y^2 -8x +4y = 30 Tangent line equation: y = x+4 Centre of circle: (4, -2) Slope of radius: -1 Radius equation: y--2 = -1(x-4) => y = -x+2 Note that this proves that tangent of a circle is always at right angles to its radius
No. A chord is a straight line within a circle that meets the circumference at two points and divides the circle into two arcs. A radius is a straight line from the centre of the circle to the circumference and is therefore not a chord. However, a diameter is a chord passing through the centre of the circle.
Circle equation: x^2 +y^2 -2x -6y +5 = 0 Completing the squares: (x-1)^2 +(y-3)^2 = 5 Centre of circle: (1, 3) Tangent line meets the x-axis at: (0, 5) Distance from (0, 5) to (1, 3) = 5 units using the distance formula
Equation of circle: x^2 +10x +y^2 -2y -39 = 0 Completing the squares: (x+5)^2 +(y-1)^2 = 65 Center of circle: (-5, 1) Slope of radius: 1/8 Slope of tangent line: -8 Point of contact: (3, 2) Equation of tangent line: y-2 = -8(x-3) => y = -8x+26 Note that the tangent line meets the radius of the circle at right angles.
The great circle is the intersection of a sphere and any plane passing through its centre. Given two distinct points on the surface of a sphere, those two points and the centre of the sphere define a plane. [If one of the points is at the antipodes of the other, an infinite number of planes are defined.] The great circle is the circle formed when that plane meets the surface of the sphere.
Equation of circle: x^2 +y^2 -2x -6y +5 = 0 Completing the squares: (x-1)^2 +(y-3)^2 = 5 Center of circle: (1, 3) Tangent line from (3, 4) meets the x axis at: (5, 0) Distance from (5, 0) to (1, 3) = 5 using the distance formula
A circle with centre (X, Y) and radius r has an equation of the form: (x - X)² + (y - Y)² = r² Completing the square in x and y for the given equation gives: x² + y² + 4x - 6y + 10 = 0 → (x + (4/2))² - (4/2)² + (y - 6/2) - (6/2)² + 10 = 0 → (x + 2)² +(y - 3)² -2² - 3² + 10 = 0 → (x - -2)² + (y - 3)² = 4 + 9 - 10 = 3 → centre of circle is (-2, 3) and radius is √3 Where a tangent meets a circle it forms a right angle with a radius of the circle. Thus the origin, point of contact of tangent and centre of the circle form a right angled triangle with the hypotenuse the side between the origin and the centre of the circle. Thus Pythagoras can be used to find the length of the hypotenuse and the tangent: tangent² + radius² = hypotenuse² → tangent = √(hypotenuse² - radius²) = √((-2 - 0)² + (3 - 0)² - 3) = √((-2)² + (3)² - 3) = √(4 + 9 - 3) = √10 units ≈ 3.16 units
Equation of circle: x^2 +y^2 -2x -6y +5 = 0 Completing the squares: (x -1)^2 +(y -3)^2 = 5 which is radius squared Center of circle: (1, 3) Tangent line is at right angles to the radius at (3, 4) and meets the x axis at (5, 0) Distance from point (5, 0) to center of circle (1, 3) = 5 units using distance formula
Point of contact: (3, 4) Circle equation: x^2 +y^2 -2x -6y+5 = 0 Completing the squares: (x-1)^2 +(y-3)^2 -1 -9 +5 = 0 So: (x-1)^2 +(y-3) = 5 Centre of circle: (1, 3) Slope of radius: (3-4)/(1-3) = 1/2 Slope of tangent: -2 Equation of tangent line: y-4 = -2(x-3) => 2x+y = 10 Tangent line meets the x axis at: (5, 0) Using formula distance from (1, 3) to (5, 0) = 5 units
From any point on the circumference of the circle, draw a line going through the center and continuing until it meets the circumference again. Measure this line. This is the diameter of the circle. If the centre is not marked, simply take a ruler and find the widest measure you can make across the circle. See the related link below, The Parts of the Circle.
Points: (7, 3) and (-6, 1) Midpoint: (0.5, 2) Slope: 2/13 Perpendicular slope: -13/2 Perpendicular equation: y-2 = -13/2(x-0.5 => 2y = -13x+10.5