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Finding the Fourth Proportional to 782.35, 1,078.54 and 487.42

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Solution

The fourth proportional to 782.35, 1,078.54 and 487.42 is: 671.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.35 : 1,078.54 = 487.42 : x
  2. Step 2: Convert to fraction form
    782.35/1,078.54 = 487.42/x
  3. Step 3: Cross multiply
    782.35x = 1,078.54 × 487.42
  4. Step 4: Simplify right side
    782.35x = 525,701.97
  5. Step 5: Solve for x
    x = 525,701.97/782.35
  6. Step 6: Final answer
    x = 671.95

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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.