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Finding the Fourth Proportional to 378.60, 522.85 and 285.20

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Solution

The fourth proportional to 378.60, 522.85 and 285.20 is: 393.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.60 : 522.85 = 285.20 : x
  2. Step 2: Convert to fraction form
    378.60/522.85 = 285.20/x
  3. Step 3: Cross multiply
    378.60x = 522.85 × 285.20
  4. Step 4: Simplify right side
    378.60x = 149,112.78
  5. Step 5: Solve for x
    x = 149,112.78/378.60
  6. Step 6: Final answer
    x = 393.86

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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.