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Finding the Fourth Proportional to 391.90, 540.86 and 217.26

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Solution

The fourth proportional to 391.90, 540.86 and 217.26 is: 299.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.90 : 540.86 = 217.26 : x
  2. Step 2: Convert to fraction form
    391.90/540.86 = 217.26/x
  3. Step 3: Cross multiply
    391.90x = 540.86 × 217.26
  4. Step 4: Simplify right side
    391.90x = 117,507.24
  5. Step 5: Solve for x
    x = 117,507.24/391.90
  6. Step 6: Final answer
    x = 299.84

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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.