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Finding the Fourth Proportional to 71.90, 99.22 and 39.15

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Solution

The fourth proportional to 71.90, 99.22 and 39.15 is: 54.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.90 : 99.22 = 39.15 : x
  2. Step 2: Convert to fraction form
    71.90/99.22 = 39.15/x
  3. Step 3: Cross multiply
    71.90x = 99.22 × 39.15
  4. Step 4: Simplify right side
    71.90x = 3,884.33
  5. Step 5: Solve for x
    x = 3,884.33/71.90
  6. Step 6: Final answer
    x = 54.03

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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.