Prentice Hall Geometry
  1. Think About a Plan Two similar rectangles have areas 27 in , . squared  and 48 in , . squared , .  The length of one side of the larger rectangle is 16 in. What are the dimensions of both rectangles?
    • How does the ratio of the similar rectangles compare to their scale factor?
    • How can you use the dimensions of the larger rectangle to find the dimensions of the smaller rectangle?
  2. The longer sides of a parallelogram are 5 m. The longer sides of a similar parallelogram are 15 m. The area of the smaller parallelogram is 28 , m squared , .  What is the area of the larger parallelogram?

Algebra Find the values of x and y when the smaller triangle shown here has the given area.

A small right triangle has vertical leg x and horizontal leg y. A large right triangle has vertical leg 8 centimeters and horizontal leg 12 centimeters. The bottom angles are congruent.

  1. 3 , cm squared
  2. 6 , cm squared
  3. 12 , cm squared
  4. 16 , cm squared
  5. 24 , cm squared
  6. 48 , cm squared
  7. Medicine For some medical imaging, the scale of the image is 3 : 1. That means that if an image is 3 cm long, the corresponding length on the person's body is 1 cm. Find the actual area of a lesion if its image has area 2 . 7 , cm squared , .
  8. In cap delta r s t comma r s . equals 20 m comma s t equals 25 m comma  and r t equals 40 m .
    1. Open-Ended Choose a convenient scale. Then use a ruler and compass to draw cap delta r , prime s . prime t prime tilde operator . cap delta r s t .
    2. Constructions Construct an altitude of cap delta r , prime s . prime t prime  and measure its length. Find the area of cap delta r , prime s . prime t prime .
    3. Estimation Estimate the area of cap delta r s t .

Compare the blue figure to the red figure. Find the ratios of (a) their perimeters and (b) their areas.

  1. A blue circle has radius 5x and a red circle has radius 2x.
  2. A blue equilateral triangle has sides 8 centimeters. A red equilateral triangle has sides 3 centimeters.
  3. A large blue right triangle has a small red right triangle inside, sharing the right angle.
    1. Find the area of a regular hexagon with sides 2 cm long. Leave your answer in simplest radical form.
    2. Use your answer to part (a) and Theorem 10-7 to find the areas of the regular hexagons shown below.

    Three hexagons have sides measuring 6 centimeters, 3 centimeters, and 8 centimeters, respectively.

  4. Writing The enrollment at an elementary school is going to increase from 200 students to 395 students. A parents' group is planning to increase the 100 ft-by-200 ft playground area to a larger area that is 200 ft by 400 ft. What would you tell the parents' group when they ask your opinion about whether the new playground will be large enough?

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Table of Contents

Prentice Hall Geometry Chapter 1 Tools of Geometry Chapter 2 Reasoning and Proof Chapter 3 Parallel and Perpendicular Lines Chapter 4 Congruent Triangles Chapter 5 Relationships Within Triangles Chapter 6 Polygons and Quadrilaterals Chapter 7 Similarity Chapter 8 Right Triangles and Trigonometry Chapter 9 Transformations Chapter 10 Area Chapter 11 Surface Area and Volume Chapter 12 Circles Skills Handbook Reference Visual Glossary Selected Answers Index Acknowledgments