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Finding the Fourth Proportional to 924.80, 1,387.20 and 487.40

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Solution

The fourth proportional to 924.80, 1,387.20 and 487.40 is: 731.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    924.80 : 1,387.20 = 487.40 : x
  2. Step 2: Convert to fraction form
    924.80/1,387.20 = 487.40/x
  3. Step 3: Cross multiply
    924.80x = 1,387.20 × 487.40
  4. Step 4: Simplify right side
    924.80x = 676,121.28
  5. Step 5: Solve for x
    x = 676,121.28/924.80
  6. Step 6: Final answer
    x = 731.10

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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.