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Finding the Fourth Proportional to 258.30, 389.22 and 213.65

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Solution

The fourth proportional to 258.30, 389.22 and 213.65 is: 321.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.30 : 389.22 = 213.65 : x
  2. Step 2: Convert to fraction form
    258.30/389.22 = 213.65/x
  3. Step 3: Cross multiply
    258.30x = 389.22 × 213.65
  4. Step 4: Simplify right side
    258.30x = 83,154.91
  5. Step 5: Solve for x
    x = 83,154.91/258.30
  6. Step 6: Final answer
    x = 321.94

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.