Geometry Circles Review

Front

What is a circle?

Back

A circle is a set of points in a plane that are equidistant from a fixed point called the center.

Front

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

Back

The standard form of a circle's equation is (x-h)² + (y-k)² = r², where (h,k) is the center and r is the radius.

Front

How do you find the radius of a circle from its equation?

Back

The radius can be found by taking the square root of the number on the right side of the equation in standard form.

Front

What does the term 'diameter' refer to in a circle?

Back

The diameter is the distance across the circle through the center, equal to twice the radius.

Front

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

Back

The diameter is twice the length of the radius (d = 2r).

Front

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

Back

To convert, complete the square for the x and y terms.

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle, calculated as C = 2πr.

Front

What is the area of a circle?

Back

The area is the space contained within the circle, calculated as A = πr².

Front

What is the significance of the center of a circle?

Back

The center is the point from which all points on the circle are equidistant.

Front

How do you determine if a point lies inside, on, or outside a circle?

Back

Calculate the distance from the point to the center. If it's less than the radius, it's inside; if equal, it's on; if greater, it's outside.