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Finding the Fourth Proportional to 721.12, 1,080.76 and 489.43

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Solution

The fourth proportional to 721.12, 1,080.76 and 489.43 is: 733.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.12 : 1,080.76 = 489.43 : x
  2. Step 2: Convert to fraction form
    721.12/1,080.76 = 489.43/x
  3. Step 3: Cross multiply
    721.12x = 1,080.76 × 489.43
  4. Step 4: Simplify right side
    721.12x = 528,956.37
  5. Step 5: Solve for x
    x = 528,956.37/721.12
  6. Step 6: Final answer
    x = 733.52

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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.