Lesson: Estimating Heights
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Teacher
Extensions

This activity was an attempt to improve an activity from a sample chapter that I received at a math conference. Here is the activity. (Compare the activity below to the lesson that I developed here.)

Estimating Heights
Do you know there are formulas relating the sizes of some parts of the human body? And these formulas are the same for all people?

For example, suppose you know only the length of a person's radius bone, r centimeters. You want to estimate this person's height, h centimeters. You can substitute the value for r in the appropriate formula below. Then solve to determine her or his approximate height.
     Female    h = 3.34r + 81.2
     Male        h = 3.27r + 85.9
1. A radius bone 24.5 cm long was found. Substitute 24.5 for r in both formulas. Use your calculator to estimate the height if the person was a female and if the person was a male.
2. a) For a female choose some values for r between 20 cm and 30 cm.
        Calculate the corresponding values of h.
        Graph the height of the person against radius bone length.
    b) Repeat part a for a male.
3. Use a computer to set up a spreadsheet like the one shown below.
    Copy the formulas in row 5 to row 6, and beyond.
    a) Describe what each formula does. Then enter an initial radius bone length length in cell A4.
    b) Use the spreadsheet to check your solutions to exercise 3.