8.6: Rectangle Facts 6
Look at Rectangle below. Notice that it has been divided into 4 smaller rectangles. Given the area of three of the smaller rectangles, can you figure out the area of the fourth? In this concept, we will practice working with the dimensions of rectangles and area of rectangles.
Guidance
In order to solve the problem about the rectangle above, use the problem solving steps.
- Start by describing what information is given.
- Then, identify what your job is. In these problems, your job will be to figure out the area of the fourth rectangle.
- Next, make a plan for how you will solve. In these problems, figure out the dimensions of the square first. Then figure out the dimensions of the other rectangles. Finally, find the area of the missing rectangle.
- Then, solve the problem. Implement your plan.
- Finally, check your solution. Verify the dimensions and area of each rectangle.
Example A
Rectangle is separated into 4 smaller rectangles.
Solution:
We can use problem solving steps to help.
Example B
Rectangle is separated into 4 smaller rectangles.
Solution:
We can use problem solving steps to help.
Example C
Rectangle is separated into 4 smaller rectangles.
Solution:
We can use problem solving steps to help.
Concept Problem Revisited
We can use problem solving steps to help.
Vocabulary
A rectangle is a 4-sided shape whose angles are all right angles. The dimensions of a rectangle are the lengths of its sides (usually called the length and width ). In general, area is a calculation of the number of unit squares it takes to fill up a shape.
Guided Practice
1. Rectangle is separated into 4 smaller rectangles.
2. Rectangle is separated into 4 smaller rectangles.
3. Rectangle is separated into 4 smaller rectangles.
Answers:
1. 6 square inches
2. 56 square inches
3. 8 square inches
Practice
For each problem below, the large rectangle has been separated into 4 smaller rectangles.
Image Attributions
Description
Learning Objectives
Students are presented with rectangles that have been divided into 4 smaller rectangles. Given the area of three of these rectangles, they are asked to find the area of the fourth. Students use problem solving steps to help.