What is the perimeter?
Perimeter
What is the perimeter?
Perimeter is the measure obtained as a result of the sum of the sides of a flat geometric figure. That is, the perimeter is what the contour of the figure measures.
The term perimeter comes from the Greek περίμετρος , a word composed of the prefix περί (peri), which means around and μετρος (metron) which means measure.
Perimeter is also a word used in military jargon to refer to a high security space.
How to remove the perimeter
To calculate the perimeter of a geometric figure it is necessary to know two basic variables:
- The number of sides of the figure.
- The length of each of those sides.
In the case of the circumference, it is necessary to know the length of the radius or its diameter in order to calculate its perimeter.
Perimeter formulas
These are the formulas to calculate the perimeter of some basic geometric figures:
Scalene triangle
A scalene triangle is one that has three unequal sides. The formula to calculate the perimeter of a scalene triangle is:
P = a + b + c
where a, b, and c are each of the sides.
An example of a perimeter in a scalene triangle with sides measuring 3, 4, and 12 cm would be:
P = 3 + 4 + 12
P = 19 cm.
Isosceles triangle
An isosceles triangle is one that has two equal sides. The formula to calculate the perimeter of an isosceles triangle in this case would be:
P = 2xl + b
An example of the perimeter in an isosceles triangle , whose sides are 37, 37, and 15 cm, would be:
P = 2x37 + 15
P = 74 + 15
P = 89 cm.
Equilateral triangle
The equilateral triangle is one that has three equal sides. The formula for the perimeter of the equilateral triangle is:
P = 3xl
An example of the perimeter in an equilateral triangle whose sides are 9 cm, would be:
P = 3x9
P = 27 cm.
Square
A square is a flat geometric figure that has four equal sides. The formula to calculate the perimeter of a square is:
P = 4xl
An example of the perimeter of a square whose sides measure 7.5 cm would be:
P = 4x7.5 cm.
P = 30 cm.
Rectangle
A rectangle is a flat geometric figure that has four sides with two different measurements (height and width). The formula to calculate the perimeter of a rectangle is:
P = 2x (a + b)
An example of the perimeter of a rectangle whose sides are 2 and 8 cm respectively, would be:
P = 2x (2 + 8)
P = 2x (10)
P = 20 cm.
Circumference
A circle is a flat, closed curved line made up of points that are equidistant from the center. The formula for the perimeter of the circle is:
P = 2π. r
An example of the perimeter of a circle whose radius is 7.47 cm would be:
P = 2x (3.14) x 7.47
P = 6.28x 7.47
P = 46.91 cm.
- Update date: March 6, 2021.