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Finding the Fourth Proportional to 381.91, 572.85 and 121.90

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Solution

The fourth proportional to 381.91, 572.85 and 121.90 is: 182.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    381.91 : 572.85 = 121.90 : x
  2. Step 2: Convert to fraction form
    381.91/572.85 = 121.90/x
  3. Step 3: Cross multiply
    381.91x = 572.85 × 121.90
  4. Step 4: Simplify right side
    381.91x = 69,830.42
  5. Step 5: Solve for x
    x = 69,830.42/381.91
  6. Step 6: Final answer
    x = 182.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.