Question

A circle has center O(−3, 1) and radius 10. Which of the following points is on the circle?

A. V(−3, −4)
B.X(5, −2)
C.Y(−6, 0)
D.Z(5, 7)

Answer 1

Try this solution:
1. common equation of circle is (x-a)²+(y-b)²=r², where a,b - coordinates of the centre, r - radius of the circle.
2. using point O and radius: (x+3)²+(y-1)²=100 - the equation of the circle.
3. substituting point V,X,Y and Z into the equation of the circle:
V: (-3+3)²+(-4-1)²=100 - false;
X: (5+3)²+(-2-1)²=100- false;
Y: (-6-3)²+(0-1)²=100 - false;
Z: (5+3)²+(7-1)²=100 - true.

Answer: D.