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Finding the Fourth Proportional to 257.81, 386.91 and 221.36

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Solution

The fourth proportional to 257.81, 386.91 and 221.36 is: 332.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.81 : 386.91 = 221.36 : x
  2. Step 2: Convert to fraction form
    257.81/386.91 = 221.36/x
  3. Step 3: Cross multiply
    257.81x = 386.91 × 221.36
  4. Step 4: Simplify right side
    257.81x = 85,644.46
  5. Step 5: Solve for x
    x = 85,644.46/257.81
  6. Step 6: Final answer
    x = 332.21

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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.