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Finding the Fourth Proportional to 878.70, 1,318.69 and 648.21

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Solution

The fourth proportional to 878.70, 1,318.69 and 648.21 is: 972.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.70 : 1,318.69 = 648.21 : x
  2. Step 2: Convert to fraction form
    878.70/1,318.69 = 648.21/x
  3. Step 3: Cross multiply
    878.70x = 1,318.69 × 648.21
  4. Step 4: Simplify right side
    878.70x = 854,788.04
  5. Step 5: Solve for x
    x = 854,788.04/878.70
  6. Step 6: Final answer
    x = 972.79

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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.