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Finding the Fourth Proportional to 395.78, 546.20 and 221.12

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Solution

The fourth proportional to 395.78, 546.20 and 221.12 is: 305.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    395.78 : 546.20 = 221.12 : x
  2. Step 2: Convert to fraction form
    395.78/546.20 = 221.12/x
  3. Step 3: Cross multiply
    395.78x = 546.20 × 221.12
  4. Step 4: Simplify right side
    395.78x = 120,771.91
  5. Step 5: Solve for x
    x = 120,771.91/395.78
  6. Step 6: Final answer
    x = 305.15

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.