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Finding the Fourth Proportional to 258.25, 389.15 and 213.60

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Solution

The fourth proportional to 258.25, 389.15 and 213.60 is: 321.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.25 : 389.15 = 213.60 : x
  2. Step 2: Convert to fraction form
    258.25/389.15 = 213.60/x
  3. Step 3: Cross multiply
    258.25x = 389.15 × 213.60
  4. Step 4: Simplify right side
    258.25x = 83,122.17
  5. Step 5: Solve for x
    x = 83,122.17/258.25
  6. Step 6: Final answer
    x = 321.87

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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.