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Finding the Fourth Proportional to 258.12, 388.96 and 213.48

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Solution

The fourth proportional to 258.12, 388.96 and 213.48 is: 321.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.12 : 388.96 = 213.48 : x
  2. Step 2: Convert to fraction form
    258.12/388.96 = 213.48/x
  3. Step 3: Cross multiply
    258.12x = 388.96 × 213.48
  4. Step 4: Simplify right side
    258.12x = 83,033.24
  5. Step 5: Solve for x
    x = 83,033.24/258.12
  6. Step 6: Final answer
    x = 321.68

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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.