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Finding the Fourth Proportional to 721.02, 1,080.39 and 489.09

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Solution

The fourth proportional to 721.02, 1,080.39 and 489.09 is: 732.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.02 : 1,080.39 = 489.09 : x
  2. Step 2: Convert to fraction form
    721.02/1,080.39 = 489.09/x
  3. Step 3: Cross multiply
    721.02x = 1,080.39 × 489.09
  4. Step 4: Simplify right side
    721.02x = 528,407.95
  5. Step 5: Solve for x
    x = 528,407.95/721.02
  6. Step 6: Final answer
    x = 732.86

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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.