E2.6 Apply the formula for the area of a rectangle to find the unknown measurement when given two of the three.
Activity 1: Problem Solving on the Area - Missing Side
Here is Mr. Claus' vegetable garden. What is the length of the unknown side at the bottom of his garden if the other side is 7 m long and the area is 28 m2?
image A vegetable garden of lettuce, carrots, beets, green onions, and tomatoes. To the left of the image of the vegetable garden is marked: seven meters. Under the image it reads: Area equal to 28 square meters.
Source: translated from En avant, les maths!, 4e année, ML, Sens de l'espace, p. 17.
Activity 2: Use the Area Formula to Find the Unknown Measurement
Present the following situation to the students.
Chilali wants to build an outdoor skating rink in her backyard. She already has two wooden boards, each measuring 9 m. Knowing that Chilali wants to build a skating rink with an area of 72 m2, what will be the size of each of the other two boards?
Ask students to explain their reasoning and demonstrate their calculations using the formula for calculating area.