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Finding the Fourth Proportional to 391.31, 539.99 and 216.65

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Solution

The fourth proportional to 391.31, 539.99 and 216.65 is: 298.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.31 : 539.99 = 216.65 : x
  2. Step 2: Convert to fraction form
    391.31/539.99 = 216.65/x
  3. Step 3: Cross multiply
    391.31x = 539.99 × 216.65
  4. Step 4: Simplify right side
    391.31x = 116,989.10
  5. Step 5: Solve for x
    x = 116,989.10/391.31
  6. Step 6: Final answer
    x = 298.97

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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.