Non Linear - Circles

Question 1

What is the formula of a circle with centre at origin and radius r

Answer 1

x^2 + y^2 = r^2

Question 2

What is the general equation of a circle with centre (h,k) and radius r

Answer 2

(x-h)^2 + (y-k)^2 = r^2

Question 3

Are the sets of coordinates on, inside or outside the circle :
(x-h)^2 + (y-k)^2 = r^2

Answer 3

On

Question 4

Are the sets of coordinates on, inside or outside the circle :
(x-h)^2 + (y-k)^2 < r^2

Answer 4

Inside

Question 5

Are the sets of coordinates on, inside or outside the circle :
(x-h)^2 + (y-k)^2 > r^2

Answer 5

Outside

Question 6

What is the equation for the upper semi-circle

Answer 6

y = square root of (r^2 - x^2)

Question 7

What is the equation for the lower semi-circle

Answer 7

y= - square root of (r^2 - x^2)

Question 8

What does the r stand for in the semi-circle and circle equation

Answer 8

Radius