Chapter 19

Using Formulas in Geometric Story Problems

Story problems (practical applications) appear in all types and levels of mathematics. A really nice feature of geometric story problems is that you can almost always find a formula to apply.

The Problems You'll Work On

From the beginning and through the middle and end, the geometric story problems in this chapter require the following skills:

  • Finding the perimeter and area of rectangles
  • Tackling trapezoids with their unequal sides
  • Squaring up with properties of squares
  • Recognizing hexagons and their usefulness in traffic control
  • Applying the Pythagorean theorem and Pythagorean triples
  • Computing the volume of a right rectangular prism
  • Determining the surface area and volume of cylinders
  • Dealing with the difference between radian and degree measures for angles
  • Using Heron's formula for the area of a triangle

What to Watch Out For

Don't get ahead of yourself when working these problems. Watch out for the following:

  • Recognizing which formula to use for which figure or application
  • Matching up the correct numbers and units with the symbols in a formula
  • Performing the formula's operations correctly

Working around the Perimeter of Rectangles

808–813 Solve the problems using the formula for the perimeter of a rectangle: P = 2(l + w).

808. What is the perimeter of a rectangular yard measuring 6 yards wide and 8 yards long?

809. If the perimeter of a rectangular plot is 400 feet, and the width is 50 feet, then what is the length ...

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