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Finding the Fourth Proportional to 71.96, 99.31 and 39.22

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Solution

The fourth proportional to 71.96, 99.31 and 39.22 is: 54.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.96 : 99.31 = 39.22 : x
  2. Step 2: Convert to fraction form
    71.96/99.31 = 39.22/x
  3. Step 3: Cross multiply
    71.96x = 99.31 × 39.22
  4. Step 4: Simplify right side
    71.96x = 3,894.78
  5. Step 5: Solve for x
    x = 3,894.78/71.96
  6. Step 6: Final answer
    x = 54.12

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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.