Use area and perimeter to determine cost
Key Notes :
Area and Cost:
- Understanding Area: Area represents the amount of space inside a shape and is measured in square units (e.g., square meters, square feet).
- Cost Calculation: In some situations, the cost of something (like carpeting, flooring, or painting) might be directly proportional to the area to be covered.
Perimeter and cost
- Understanding Perimeter: Perimeter is the distance around the outside of a shape. It’s like measuring the length of a fence around a garden or the outline of a playground.
- Cost calculation : costs can be directly proportional to perimeter when materials are priced per unit length
Learn with an example
⚫ A photograph is 12 centimetres by 18 centimetres. A frame shop charges ₹83.00 per centimetre for a silver frame. How much would it cost to buy a silver frame for the photograph?
₹_____
Picture the rectangle:
Add the lengths:
12 + 18 + 12 + 18 = 60
The perimeter is 60 centimetres. Now multiply the price per centimetre by the perimeter.
It would cost ₹4,980.00 to buy a silver frame for the photograph.
⚫ The sides of a square-shaped room are 4 metres long. Levi wants to buy carpet to cover the floor of the room. If the carpet costs ₹3,104.00 per square metre, how much will it cost to buy enough carpet for the room?
₹_____
Multiply the side length by itself:
4 × 4 = 16
The area is 16 square metres. Now multiply the price per square metre by the area.
It will cost ₹49,664.00.
⚫ Levi’s lounge is 5 metres wide and 8 metres long. He wants to put a border around the top of the room. The cost of the border is ₹212.00 per metre. How much will it cost to buy enough of the border to go around the room?
₹_____
Picture the rectangle:
Add the lengths:
5 + 8 + 5 + 8 = 26
The perimeter is 26 metres. Now multiply the price per metre by the perimeter.
It will cost ₹5,512.00 to buy enough border.
Let’s practice!🖊️
