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Finding the Fourth Proportional to 285.12, 392.85 and 255.15

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Solution

The fourth proportional to 285.12, 392.85 and 255.15 is: 351.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.12 : 392.85 = 255.15 : x
  2. Step 2: Convert to fraction form
    285.12/392.85 = 255.15/x
  3. Step 3: Cross multiply
    285.12x = 392.85 × 255.15
  4. Step 4: Simplify right side
    285.12x = 100,235.68
  5. Step 5: Solve for x
    x = 100,235.68/285.12
  6. Step 6: Final answer
    x = 351.56

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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.