– The length around the
outside of a geometric figure.
Area – A measure of the amount of space enclosed by a
two-dimensional geometric figure. The area equals the number of square
units contained inside the figure.
Volume – A measure of the amount of space enclosed by a
three-dimensional geometric figure. The volume equals the number of cubic
units contained inside the figure.
Here are some basic geometric formulas for finding
perimeter, area, and volume:
Triangles: The perimeter of a triangle is the sum of its three
sides. The area of a triangle is:
See the Geometry page for a discussion on the base and
height of a triangle. The height you use depends on which side of the
triangle is chosen to be the base. Note that for a right triangle the two
short sides form the base and height of the triangle.
Rectangles and Parallelograms: The perimeter is the sum of the
four sides of the figure. The area is:
Circle: The perimeter of a circle is often called the
circumference of the circle. The circumference and area are found using
the formulas:
r is the radius of the circle and
