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Finding the Fourth Proportional to 381.21, 571.89 and 121.15

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Solution

The fourth proportional to 381.21, 571.89 and 121.15 is: 181.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    381.21 : 571.89 = 121.15 : x
  2. Step 2: Convert to fraction form
    381.21/571.89 = 121.15/x
  3. Step 3: Cross multiply
    381.21x = 571.89 × 121.15
  4. Step 4: Simplify right side
    381.21x = 69,282.43
  5. Step 5: Solve for x
    x = 69,282.43/381.21
  6. Step 6: Final answer
    x = 181.74

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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.