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Finding the Fourth Proportional to 258.71, 386.21 and 221.75

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Solution

The fourth proportional to 258.71, 386.21 and 221.75 is: 331.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.71 : 386.21 = 221.75 : x
  2. Step 2: Convert to fraction form
    258.71/386.21 = 221.75/x
  3. Step 3: Cross multiply
    258.71x = 386.21 × 221.75
  4. Step 4: Simplify right side
    258.71x = 85,640.96
  5. Step 5: Solve for x
    x = 85,640.96/258.71
  6. Step 6: Final answer
    x = 331.03

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.