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Points on a circle
CONCEPTS
Circle Equation and Point on a Circle
• Any point that is on a circle can be put into the circle equation.
EXAMPLE
• Point (2, 3) is lies on the circle with center (1, 1) => (x – 1)² + (y – 1)² = 2 => (2 – 1)² + (3 – 1)² = 5
PRACTICE PROBLEMS
Question 1 Given the circle x² + y² = 25, if point, (3, y) is on the circle, what is y coordinate?
-- Answer -- (3, 4)
Stick (3, y) into the circle equation
3² + y² = 25 => y² = 16 => y = 4
ACT PRACTICE PROBLEMS
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