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Finding the Fourth Proportional to 819.20, 1,130.42 and 487.71

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Solution

The fourth proportional to 819.20, 1,130.42 and 487.71 is: 672.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.20 : 1,130.42 = 487.71 : x
  2. Step 2: Convert to fraction form
    819.20/1,130.42 = 487.71/x
  3. Step 3: Cross multiply
    819.20x = 1,130.42 × 487.71
  4. Step 4: Simplify right side
    819.20x = 551,317.14
  5. Step 5: Solve for x
    x = 551,317.14/819.20
  6. Step 6: Final answer
    x = 672.99

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.