Geometrymedium · Past Paper
What is the length of the radius of the circle x^2 + y^2 - 2x - 4y - 20 = 0?
A5
B20
Csqrt(20)
D25
✓ Correct Answer: A — 5
g = -1, f = -2, c = -20. r = sqrt(g^2 + f^2 - c) = sqrt((-1)^2 + (-2)^2 - (-20)) = sqrt(1+4+20) = 5.
Share this question
More from Geometry
- If the transversal of two parallel lines creates an interior angle of 2x and a corresponding angle of 60, find x.
- If an angle is 2/3 of a right angle, what is its measure?
- Which of the following describes an obtuse-angled triangle?
- Find the measure of an angle whose supplement is 4 times its complement.
- A line passes through (2, 2) and is perpendicular to y = x. Its equation is: