Radius = 1111
If you mean: x^2 + y^2 = 121 then the radius is the square root of 121 which is 11
X2 + y2 = 100 = r2 r = 10
If x^2 plus y^2 = 169 then the center of the circle is at (0, 0) and its radius is the square root of 169 which is 13
The ' 1 ' in that equation is the radius.
it equals LxL+WxW
The center of the circle is at (0, 0) and its radius is the square root of 1 which is 1
sqrt 36 ie 6
10. Equation of circle is x2 + y2 = r2. Consider: when x = 0 y2 must = 100 so y = 10 which describes a circle centre the origin, radius 10. Similarly when x = 10 y must be 0.
Answer a.
The circles are concentric with centre (0,0). The radius of the outer circle is sqrt(72), that of the inner circle is sqrt(18). By Pythagoras, the length of the semichord is sqrt(72 - 18) = sqrt(54) units. Therefore the chord is 2*sqrt(54) = 6*sqrt(6) = 14.679 units (approx).
7