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Finding the Fourth Proportional to 386.91, 580.05 and 213.39

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Solution

The fourth proportional to 386.91, 580.05 and 213.39 is: 319.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.91 : 580.05 = 213.39 : x
  2. Step 2: Convert to fraction form
    386.91/580.05 = 213.39/x
  3. Step 3: Cross multiply
    386.91x = 580.05 × 213.39
  4. Step 4: Simplify right side
    386.91x = 123,776.87
  5. Step 5: Solve for x
    x = 123,776.87/386.91
  6. Step 6: Final answer
    x = 319.91

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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.