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Finding the Fourth Proportional to 72.69, 100.31 and 39.95

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Solution

The fourth proportional to 72.69, 100.31 and 39.95 is: 55.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.69 : 100.31 = 39.95 : x
  2. Step 2: Convert to fraction form
    72.69/100.31 = 39.95/x
  3. Step 3: Cross multiply
    72.69x = 100.31 × 39.95
  4. Step 4: Simplify right side
    72.69x = 4,006.98
  5. Step 5: Solve for x
    x = 4,006.98/72.69
  6. Step 6: Final answer
    x = 55.12

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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.