Circles Flashcard

Front

What is a circle?

Back

A circle is a shape consisting of all points in a plane that are at a given distance (radius) from a fixed point (center).

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

What is the formula for the area of a circle?

Back

The area (A) of a circle is given by the formula: A = πr², where 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 calculate the area of a sector?

Back

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

Front

What is the relationship between degrees and radians?

Back

Degrees and radians are two units for measuring angles. 180 degrees is equal to π radians.

Front

What is the measure of a full circle in degrees?

Back

A full circle measures 360 degrees.

Front

What is the measure of a right angle in degrees?

Back

A right angle measures 90 degrees.

Front

What is the formula for the circumference of a circle given the diameter?

Back

The circumference (C) can also be calculated using the diameter (d) with the formula: C = πd.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through the center, equal to twice the radius (d = 2r).