Category: 03. Perimeter and area of shapes

  • Area of triangles

    This lesson will show you different ways to find the area of triangles. By definition, the area of a triangle is the amount of space taken by the triangle in a two-dimensional plane.  Area of a triangle formula The most common way to find the area of a triangle is to use the basic formula…

  • Area of shapes

    By definition, the area of shapes is the amount of space inside those shapes.You can find the area of any two-dimensional shape or any shape that has a width and a length The area can only be found for flat surfaces, so it does not make sense to say, ” What is the area of…

  • Perimeter formulas

    Here, find the perimeter formulas for some regular polygons. A regular polygon is a polygon with equal sides and equal angles. If we let s be the length of one sides, we can find the perimeter as demonstrated in this lesson Equilateral triangle: Perimeter = s + s + s Perimeter = 3 × s…

  • Find the perimeter in the coordinate plane

    In order to find the perimeter in the coordinate plane, you can use the ruler postulate and the distance formula. Example #1 Find the perimeter of triangle ABC in the figure below Find the length of each side of the triangle. Then, add the lengths to find the perimeter. Using the ruler postulate, AB =…

  • Circumference of a circle – Definition, formula, and examples

    The circumference of a circle, also called the perimeter of a circle, is the distance around a circle or any circular object such as a clock, a pizza, or a dinner plate. For example, the distance around a circular clock is the circumference of the clock.  How to find the circumference of a circle? Method…

  • Perimeter of a trapezoid

    The perimeter of a trapezoid where a, b, c, d are the lengths of its sides can be found using the formula p = a + b + c + d. Just like any other two-dimensional figures, the perimeter is just the sum of the lengths of the sides. Example #1: Find the perimeter for the trapezoid…

  • Perimeter of a triangle

    The perimeter of a triangle is the distance around the triangle. In other words, the perimeter is the sum of the lengths of the sides of the triangle. You will learn different ways to find the perimeter based on the different types of triangles.  Perimeter of a triangle formula Start with a scalene triangle and…

  • Perimeter of a rectangle

    Finding the perimeter of a rectangle when the length and the width are given and finding the length or the width when the perimeter is given are the goals of this lesson. Start with the rectangle below and label the width w and the length l. Given a rectangle with side length (l) and width…

  • Perimeter of a square

    The perimeter of a square is the distance around the square. In other words, the perimeter is the sum of the lengths of its sides. Since the sides of a square are all equal, you can just multiply the length of one side by 4 to get the perimeter. Derivation of perimeter of square formula…

  • Finding the perimeter

    Finding the perimeter of a shape means that you are looking for the distance around the outside of that shape. Example #1 Find the distance around for the following irregular polygon Distance around = 5 inches + 4 inches + 2 inches + 3 inches + 6 inches = 20 inches Example #2 Find the distance around…