Circles

Front

What is the standard equation of a circle with center (h, k) and radius r?

Back

(x - h)² + (y - k)² = r²

Front

How do you convert the general form of a circle's equation to standard form?

Back

You must complete the square.

Front

What is the center of the circle represented by the equation (x + 3)² + (y - 4)² = 16?

Back

The center is (-3, 4).

Front

What is the radius of the circle represented by the equation (x - 1)² + (y + 2)² = 25?

Back

The radius is 5.

Front

If a circle has a center at (0, 0) and a radius of 4, what is its standard equation?

Back

x² + y² = 16.

Front

What is the measure of an angle formed by two tangents drawn from a point outside a circle?

Back

The angle is half the difference of the measures of the intercepted arcs.

Front

What is the relationship between the radius and the diameter of a circle?

Back

The diameter is twice the length of the radius.

Front

If the measure of arc AB is 60°, what is the measure of the inscribed angle that intercepts arc AB?

Back

The inscribed angle is 30°.

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where r is the radius.

Front

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

Back

Area = πr² = 9π.