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Finding the Fourth Proportional to 257.19, 386.60 and 221.55

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Solution

The fourth proportional to 257.19, 386.60 and 221.55 is: 333.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.19 : 386.60 = 221.55 : x
  2. Step 2: Convert to fraction form
    257.19/386.60 = 221.55/x
  3. Step 3: Cross multiply
    257.19x = 386.60 × 221.55
  4. Step 4: Simplify right side
    257.19x = 85,650.12
  5. Step 5: Solve for x
    x = 85,650.12/257.19
  6. Step 6: Final answer
    x = 333.02

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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.