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Finding the Fourth Proportional to 391.28, 539.98 and 216.64

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Solution

The fourth proportional to 391.28, 539.98 and 216.64 is: 298.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.28 : 539.98 = 216.64 : x
  2. Step 2: Convert to fraction form
    391.28/539.98 = 216.64/x
  3. Step 3: Cross multiply
    391.28x = 539.98 × 216.64
  4. Step 4: Simplify right side
    391.28x = 116,981.27
  5. Step 5: Solve for x
    x = 116,981.27/391.28
  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.