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Finding the Fourth Proportional to 72.31, 108.49 and 31.71

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Solution

The fourth proportional to 72.31, 108.49 and 31.71 is: 47.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.31 : 108.49 = 31.71 : x
  2. Step 2: Convert to fraction form
    72.31/108.49 = 31.71/x
  3. Step 3: Cross multiply
    72.31x = 108.49 × 31.71
  4. Step 4: Simplify right side
    72.31x = 3,440.22
  5. Step 5: Solve for x
    x = 3,440.22/72.31
  6. Step 6: Final answer
    x = 47.58

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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.