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Finding the Fourth Proportional to 381.12, 571.78 and 121.13

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Solution

The fourth proportional to 381.12, 571.78 and 121.13 is: 181.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    381.12 : 571.78 = 121.13 : x
  2. Step 2: Convert to fraction form
    381.12/571.78 = 121.13/x
  3. Step 3: Cross multiply
    381.12x = 571.78 × 121.13
  4. Step 4: Simplify right side
    381.12x = 69,256.85
  5. Step 5: Solve for x
    x = 69,256.85/381.12
  6. Step 6: Final answer
    x = 181.72

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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.