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Finding the Fourth Proportional to 782.47, 1,078.85 and 487.23

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Solution

The fourth proportional to 782.47, 1,078.85 and 487.23 is: 671.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.47 : 1,078.85 = 487.23 : x
  2. Step 2: Convert to fraction form
    782.47/1,078.85 = 487.23/x
  3. Step 3: Cross multiply
    782.47x = 1,078.85 × 487.23
  4. Step 4: Simplify right side
    782.47x = 525,645.26
  5. Step 5: Solve for x
    x = 525,645.26/782.47
  6. Step 6: Final answer
    x = 671.78

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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.