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Finding the Fourth Proportional to 865.87, 1,298.78 and 216.61

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Solution

The fourth proportional to 865.87, 1,298.78 and 216.61 is: 324.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.87 : 1,298.78 = 216.61 : x
  2. Step 2: Convert to fraction form
    865.87/1,298.78 = 216.61/x
  3. Step 3: Cross multiply
    865.87x = 1,298.78 × 216.61
  4. Step 4: Simplify right side
    865.87x = 281,321.16
  5. Step 5: Solve for x
    x = 281,321.16/865.87
  6. Step 6: Final answer
    x = 324.90

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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.