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Home > MC1 > Chapter 4 > Lesson 4.2.1 > Problem 4-55

4-55.
  1. . Here are some new distances with given lengths to help Cecil cross the tightrope. Find at least two ways to get Cecil across for each situation. Write your solutions in symbolic form. 4-55a HW eTool (CPM), 4-55b HW eTool (CPM), 4-55c HW eTool (CPM). Homework Help ✎

    1. Span of tightrope: 19 feet
      Given lengths: 4, 5, 7 feet

    2. Span of tightrope: 25 feet
      Given lengths: 3, 6, 7 feet

    3. Span of tightrope: 23 feet
      Given lengths: 5, 2, 9 feet

Explore part (a) with the eTool below.
Click the link at right for the full version of the eTool: MC1 4-55a HW eTool

How can you add or subtract any number of 4's, 5's, and 7's to make 19?

4 + 4 + 4 + 7, or 3(4) + 7, is one way of solving this problem. Can you find at least one more solution?

If you multiply 6 by 3, how far from 25 is the product? Answer that question and use it as a starting point for your solution. Remember to check your work!

Explore part (b) with the eTool below.
Click the link at right for the full version of the eTool: MC1 4-55b HW eTool

This problem is very similar to parts (a) and (b). Try starting with one number and see how close you can get to 23 using just that number. Then see if one of the other lengths can help you finish.

Explore part (c) with the eTool below.
Click the link at right for the full version of the eTool: MC1 4-55c HW eTool