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Finding the Fourth Proportional to 787.78, 1,087.12 and 456.31

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Solution

The fourth proportional to 787.78, 1,087.12 and 456.31 is: 629.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.78 : 1,087.12 = 456.31 : x
  2. Step 2: Convert to fraction form
    787.78/1,087.12 = 456.31/x
  3. Step 3: Cross multiply
    787.78x = 1,087.12 × 456.31
  4. Step 4: Simplify right side
    787.78x = 496,062.60
  5. Step 5: Solve for x
    x = 496,062.60/787.78
  6. Step 6: Final answer
    x = 629.70

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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.