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Finding the Fourth Proportional to 724.98, 991.91 and 721.92

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Solution

The fourth proportional to 724.98, 991.91 and 721.92 is: 987.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    724.98 : 991.91 = 721.92 : x
  2. Step 2: Convert to fraction form
    724.98/991.91 = 721.92/x
  3. Step 3: Cross multiply
    724.98x = 991.91 × 721.92
  4. Step 4: Simplify right side
    724.98x = 716,079.67
  5. Step 5: Solve for x
    x = 716,079.67/724.98
  6. Step 6: Final answer
    x = 987.72

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.