Josh needs 1.2 pounds of wood for birdhouses. This wood weighs 0.4 pounds per square foot.
Challenge
Josh plans to make birdhouses to sell at a craft fair. He has a sample of the wood he wants to use. The sample has an area of 5 square feet and weighs 2 pounds. The local hardware store sells the wood only by the square yard. There are 9 square feet in 1 square yard.
Unit rate
A unit rate is a comparison of two quantities in different units. In this case, we want to know the unit rate for pounds of the wood per square yard.
To find the unit rate, we can divide the number of pounds by the number of square feet:
2 pounds / 5 square feet = 0.4 pounds per square foot
Therefore, each square foot of wood weighs 0.4 pounds.
Amount of wood needed
Josh needs 3 square yards of the wood in all. To find the total amount of wood he needs, we can multiply the unit rate by the number of square yards:
0.4 pounds per square foot * 3 square yards = 1.2 pounds
Therefore, Josh needs 1.2 pounds of wood to make his birdhouses.