Virginia SOL Math / Grade 4 / Measurement & Geometry
Area & Perimeter Formulas
What you'll learn
- Develop and use the formula for the perimeter of a rectangle and square
- Develop and use the formula for the area of a rectangle and square
- Solve problems in context involving area and perimeter
Words to know
- Area —
- the number of square units that cover a shape
- Perimeter —
- the distance all the way around a shape
- Length —
- the longer side of a rectangle
- Width —
- the shorter side of a rectangle
- Formula —
- a rule written with numbers and symbols
Why it matters Formulas let us find how much space a floor covers or how much fence a yard needs without counting every unit.
Worked examples
Model ItI do
Find the area of a rectangle 8 cm long and 5 cm wide.
Area of a rectangle is length times width: 8 x 5 = 40. So the area is 40 square cm.
Try It TogetherWe do
Find the perimeter of a rectangle 8 cm long and 5 cm wide.
Perimeter adds all four sides: 8 + 5 + 8 + 5 = 26. (Or use 2 x (8 + 5) = 26.) So the perimeter is 26 cm.
Now YouYou do
A square has sides of 7 feet. Find its area and perimeter.
For area multiply side by side; for perimeter add all four sides. Check your answers in the back.
Practice
Mastered 0 of 11
Warm-up
Ease in with the basics.
1.Find the area of a rectangle 3 units by 4 units.
2.Find the perimeter of a rectangle 3 units by 4 units.
3.A square has sides of 5 cm. Find its perimeter.
On Level
The core Quick Check from the book.
1.Find the area of a rectangle 9 units by 6 units.
2.Find the perimeter of a rectangle 9 units by 6 units.
3.A square has sides of 8 cm. Find its area.
4.A square has sides of 8 cm. Find its perimeter.
5.A garden is 12 ft by 4 ft. How much fence goes around it?
Challenge
Stretch your thinking.
1.A rectangle is 15 ft long and 8 ft wide. Find its area.
2.A rectangle has an area of 48 square cm and a length of 8 cm. What is its width?
3.A square garden has a perimeter of 36 feet. How long is each side?