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Finding the Fourth Proportional to 72.42, 108.68 and 31.84

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Solution

The fourth proportional to 72.42, 108.68 and 31.84 is: 47.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.42 : 108.68 = 31.84 : x
  2. Step 2: Convert to fraction form
    72.42/108.68 = 31.84/x
  3. Step 3: Cross multiply
    72.42x = 108.68 × 31.84
  4. Step 4: Simplify right side
    72.42x = 3,460.37
  5. Step 5: Solve for x
    x = 3,460.37/72.42
  6. Step 6: Final answer
    x = 47.78

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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.