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Finding the Fourth Proportional to 787.60, 1,181.40 and 648.40

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Solution

The fourth proportional to 787.60, 1,181.40 and 648.40 is: 972.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.60 : 1,181.40 = 648.40 : x
  2. Step 2: Convert to fraction form
    787.60/1,181.40 = 648.40/x
  3. Step 3: Cross multiply
    787.60x = 1,181.40 × 648.40
  4. Step 4: Simplify right side
    787.60x = 766,019.76
  5. Step 5: Solve for x
    x = 766,019.76/787.60
  6. Step 6: Final answer
    x = 972.60

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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.