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Finding the Fourth Proportional to 72.39, 108.49 and 31.76

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Solution

The fourth proportional to 72.39, 108.49 and 31.76 is: 47.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.39 : 108.49 = 31.76 : x
  2. Step 2: Convert to fraction form
    72.39/108.49 = 31.76/x
  3. Step 3: Cross multiply
    72.39x = 108.49 × 31.76
  4. Step 4: Simplify right side
    72.39x = 3,445.64
  5. Step 5: Solve for x
    x = 3,445.64/72.39
  6. Step 6: Final answer
    x = 47.60

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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.