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Finding the Fourth Proportional to 787.47, 1,179.90 and 478.38

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Solution

The fourth proportional to 787.47, 1,179.90 and 478.38 is: 716.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.47 : 1,179.90 = 478.38 : x
  2. Step 2: Convert to fraction form
    787.47/1,179.90 = 478.38/x
  3. Step 3: Cross multiply
    787.47x = 1,179.90 × 478.38
  4. Step 4: Simplify right side
    787.47x = 564,440.56
  5. Step 5: Solve for x
    x = 564,440.56/787.47
  6. Step 6: Final answer
    x = 716.78

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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.