Section C: Practice Problems Find Area of Figures Composed of Rectangles

Section Summary

Details

In this section, we found the area of figures that could be decomposed into rectangles. We added the area of each rectangle to find the area of the entire figure.

We also found missing side lengths by using what we know about opposite sides of rectangles.

6-sided shape.

Problem 1 (Lesson 12)

What is the area of this figure in square units? Explain or show your reasoning.

A figure with same size square units.

Problem 2 (Lesson 13)

Find the area of this figure. Explain or show your reasoning.

6-sided shape. Straight sides. All side lengths meet at right angles. Bottom, 5 ft. Right side rises 6 ft, then goes right 5 ft, up 4 ft. Top side length, 10 ft. Left side length, 10 ft.  

Problem 3 (Lesson 14)

Find the area of this figure. Explain or show your reasoning.

6-sided shape. Straight sides. All side lengths meet at right angles. Bottom, question mark feet. Right side rises question mark feet then goes left 5 feet, then down 2 feet and left 3 feet. Left side 8 feet.

Problem 4 (Exploration)

Lin says that she knows how to find the area of the figure. Diego says there is not enough information to find the area.

Do you agree with Lin or with Diego? Explain your reasoning.

Long description: 6-sided shape. Straight sides. All side lengths meet at right angles. Side lengths: Bottom, question mark ft. Right side rises question mark ft, then goes left question mark ft, down 2 ft, left question mark ft, and down question mark ft.

Problem 5 (Exploration)

  1. Each image shows part of a shape filled with squares.

    A shape partially filled with squares.
    Square with unit squares around perimeter. Center empty. Length, 6 unit squares. Width, 6 unit squares.

    For each image, which do you think is greater, the number of squares in the image or the number of squares missing in the middle?

  2. Check whether or not your answers are correct.