Let's say John wants to build a fence around his yard.
How much does he need to spend on materials for the fence?
Imagine this is John's yard.
John finds out that it costs $8 per foot to build the fence.
What is the total cost of the fence?
There are two steps.
1️⃣ First, find the perimeter of the space.
Perimeter is the distance around an object or space.
We see only two numbers in the picture above.
What are the dimensions of the other two sides?
Tip:
Opposite sides in a rectangle have equal lengths.
This means that we add the length of all the sides like this:
54 + 54 + 48 + 48 = 204 feet
The second step in finding the cost is to multiply the total perimeter by the cost of material per foot.
204 feet × $8 per foot = $1,632
The total cost of the materials for the fence is $1,632. ✅
After John completes his fence, he decides he wants to cover his yard with fresh grass.
The cost of grass is $2 per square foot.
How much will it cost to cover the area with grass?
1️⃣ First, we need to find the area of the space.
Area is the amount of space within a 2D, or flat, shape.
What is the formula for area? 🤔
You got it.
We multiply the length and width together.
Length × Width = Area
Let's plug in the values for John's yard.
54 × 48 = 2,592 square feet (sq ft)
To know the total cost to cover an area, multiply the area with the cost per unit of area.
🖐 Pause for a moment. Let's read that key point one more time:
To know the total cost to cover an area, multiply the area with the cost per unit of area.
Let's try it:
2,592 sq ft × $2 per sq ft = $5,184
The total cost of covering the yard with grass is $5,184. ✅
Great work.
Now, you're ready for the practice.