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Finding the Fourth Proportional to 721.68, 1,081.47 and 392.34

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Solution

The fourth proportional to 721.68, 1,081.47 and 392.34 is: 587.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.68 : 1,081.47 = 392.34 : x
  2. Step 2: Convert to fraction form
    721.68/1,081.47 = 392.34/x
  3. Step 3: Cross multiply
    721.68x = 1,081.47 × 392.34
  4. Step 4: Simplify right side
    721.68x = 424,307.26
  5. Step 5: Solve for x
    x = 424,307.26/721.68
  6. Step 6: Final answer
    x = 587.95

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.