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Finding the Fourth Proportional to 747.68, 1,121.70 and 439.80

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Solution

The fourth proportional to 747.68, 1,121.70 and 439.80 is: 659.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    747.68 : 1,121.70 = 439.80 : x
  2. Step 2: Convert to fraction form
    747.68/1,121.70 = 439.80/x
  3. Step 3: Cross multiply
    747.68x = 1,121.70 × 439.80
  4. Step 4: Simplify right side
    747.68x = 493,323.66
  5. Step 5: Solve for x
    x = 493,323.66/747.68
  6. Step 6: Final answer
    x = 659.81

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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.