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Finding the Fourth Proportional to 391.90, 540.87 and 380.05

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Solution

The fourth proportional to 391.90, 540.87 and 380.05 is: 524.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.90 : 540.87 = 380.05 : x
  2. Step 2: Convert to fraction form
    391.90/540.87 = 380.05/x
  3. Step 3: Cross multiply
    391.90x = 540.87 × 380.05
  4. Step 4: Simplify right side
    391.90x = 205,557.64
  5. Step 5: Solve for x
    x = 205,557.64/391.90
  6. Step 6: Final answer
    x = 524.52

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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.