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Finding the Fourth Proportional to 391.72, 540.56 and 217.08

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Solution

The fourth proportional to 391.72, 540.56 and 217.08 is: 299.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.72 : 540.56 = 217.08 : x
  2. Step 2: Convert to fraction form
    391.72/540.56 = 217.08/x
  3. Step 3: Cross multiply
    391.72x = 540.56 × 217.08
  4. Step 4: Simplify right side
    391.72x = 117,344.76
  5. Step 5: Solve for x
    x = 117,344.76/391.72
  6. Step 6: Final answer
    x = 299.56

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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.