Circles, arc length, sector, equations simple

Front

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

Back

The equation is (x - h)² + (y - k)² = r².

Front

What is the formula for the area of a circle?

Back

The area A of a circle is given by A = πr², where r is the radius.

Front

How do you calculate the circumference of a circle?

Back

The circumference C of a circle is given by C = 2πr, where r is the radius.

Front

What is the formula for arc length?

Back

Arc length L = (θ/360) × 2πr, where θ is the central angle in degrees and r is the radius.

Front

What is a sector of a circle?

Back

A sector is a portion of a circle enclosed by two radii and the arc between them.

Front

How do you find the area of a sector?

Back

Area of a sector = (θ/360) × πr², where θ is the central angle in degrees.

Front

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

Back

The diameter d is twice the radius: d = 2r.

Front

What is the central angle of a circle?

Back

A central angle is an angle whose vertex is at the center of the circle and whose sides intersect the circle.

Front

How do you convert radians to degrees?

Back

To convert radians to degrees, multiply by (180/π).

Front

What is the formula for the area of a circle with a given diameter?

Back

Area A = (π/4) × d², where d is the diameter.