10. Shapes and angles
10.14 Perimeter and area
Lesson
Are you ready?
Let's review how to find the perimeter and how to find the area of a rectangle.
Find the perimeter of the rectangle shown.
Find the area of the rectangle shown.
 |
width = $2$2 cm |
| length = $12$12 cm |
$\text{Area }$Area $=$= $\text{length }\times\text{width }$length ×width cm2 $\text{Area }$Area $=$= $\editable{}\times\editable{}$× cm2 (Fill in the values for the length and width.) $\text{Area }$Area $=$= $\editable{}$ cm2 (Complete the multiplication to find the area.)
Learn
You may have noticed already that shapes with the same perimeter don't always have the same area, as shown in the rectangles below. Similarly, shapes with the same area don't always have the same perimeter.
This video looks at the relationship between perimeter and area.
Apply
Which of these rectangles has an area of $24$24 cm2 and a perimeter of $20$20 cm?
(Note: Diagrams are not to scale.)
$2$2 cm $5$5 cm A$4$4 cm $6$6 cm B$3$3 cm $7$7 cm C$3$3 cm $8$8 cm D
Remember!
Rectangles can have the same perimeter and have different areas.