Unit Flashcard: Circles

Front

What is the formula for the circumference of a circle?

Back

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

Front

How do you find the area of a circle?

Back

The area (A) of a circle is calculated using the formula: A = πr², where r is the radius.

Front

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

Back

The diameter (d) of a circle is twice the radius: d = 2r.

Front

How do you calculate the arc length of a circle?

Back

Arc length (L) can be calculated using the formula: 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

The area (A) of a sector can be calculated using the formula: A = (θ/360) * πr², where θ is the central angle in degrees and r is the radius.

Front

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

Back

If the diameter (d) is known, the area (A) can be calculated using: A = π(d/2)².

Front

What is the central angle of a circle?

Back

The central angle is the angle formed at the center of the circle by two radii.

Front

How do you convert the area of a sector to find the central angle?

Back

To find the central angle (θ) from the area of a sector, use: θ = (Area * 360) / (πr²).

Front

What is the relationship between arc length and radius?

Back

Arc length is directly proportional to the radius; as the radius increases, the arc length increases for a given central angle.