Perimeter

Learning Objectives Define perimeter and explain its meaning in their own words. Calculate the perimeter of squares and rectangles using appropriate formulas. Determine the perimeter of any polygon by adding the lengths of all its sides. Solve real-world problems involving perimeter, including those with decimal and fractional side lengths. Identify and use standard units of length when calculating perimeter. Find a missing side length of a polygon when given its perimeter and the lengths of the other sides. Have you ever wondered how much ribbon you'd need to go around a gift box, or how much fencing to put around a garden? 🎁 That's where perimeter comes in handy! In this lesson, you'll learn all about perimeter – what it is, how to calculate it for differe...

TermDefinitionExample PerimeterThe total distance around the outside edge of a two-dimensional shape.If you walk all the way around the edge of a rectangular park, the total distance you walked is the park's perimeter. PolygonA closed two-dimensional shape made up of three or more straight line segments.Triangles, squares, rectangles, and hexagons are all examples of polygons. Side LengthThe measurement of one of the straight line segments that form the boundary of a polygon.A square has four equal side lengths. If one side is 5 cm, all sides are 5 cm. Unit of LengthA standard measurement used to express how long something is, such as centimeters (cm), meters (m), inches (in), or feet (ft).When we say a table is 1.5 meters long, 'meters' is the unit of length. RectangleA fo...

Perimeter of Any Polygon $P = s_1 + s_2 + s_3 + ... + s_n$ To find the perimeter of any polygon, simply add the lengths of all its sides together. This rule works for triangles, pentagons, and irregular shapes too. Perimeter of a Rectangle $P = 2 imes (l + w)$ or $P = 2l + 2w$ For a rectangle with length ($l$) and width ($w$), you can add the length and width and then multiply by 2, or add two lengths and two widths. This is a shortcut because opposite sides are equal. Perimeter of a Square $P = 4 imes s$ For a square with side length ($s$), since all four sides are equal, you can multiply the length of one side by 4 to find the perimeter.