Unit 7.1 Equation of a Circle

Front

What is the standard form of the equation of a circle?

Back

(x - h)² + (y - k)² = r², where (h, k) is the center and r is the radius.

Front

What does the variable 'r' represent in the equation of a circle?

Back

The radius of the circle.

Front

What does the variable '(h, k)' represent in the equation of a circle?

Back

The coordinates of the center of the circle.

Front

How do you find the radius from the equation (x + 3)² + (y - 2)² = 16?

Back

The radius is the square root of 16, which is 4.

Front

What is the center of the circle in the equation (x - 1)² + (y + 5)² = 36?

Back

The center is (1, -5).

Front

What is the circumference of a circle with a radius of 3?

Back

Circumference = 2πr = 2π(3) = 6π.

Front

What is the area of a circle with a radius of 4?

Back

Area = πr² = π(4)² = 16π.

Front

Which of the following is NOT an equation of a circle: x² + y² = 25 or x + y = 10?

Back

x + y = 10 is NOT an equation of a circle.

Front

What is the radius of the circle represented by the equation (x - 2)² + (y + 1)² = 9?

Back

The radius is 3.

Front

If the center of a circle is at (0, 0) and the radius is 5, what is the equation of the circle?

Back

x² + y² = 25.