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Finding the Fourth Proportional to 381.21, 571.81 and 137.67

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Solution

The fourth proportional to 381.21, 571.81 and 137.67 is: 206.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    381.21 : 571.81 = 137.67 : x
  2. Step 2: Convert to fraction form
    381.21/571.81 = 137.67/x
  3. Step 3: Cross multiply
    381.21x = 571.81 × 137.67
  4. Step 4: Simplify right side
    381.21x = 78,723.68
  5. Step 5: Solve for x
    x = 78,723.68/381.21
  6. Step 6: Final answer
    x = 206.51

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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.