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Finding the Fourth Proportional to 77.18, 115.82 and 31.55

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Solution

The fourth proportional to 77.18, 115.82 and 31.55 is: 47.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.18 : 115.82 = 31.55 : x
  2. Step 2: Convert to fraction form
    77.18/115.82 = 31.55/x
  3. Step 3: Cross multiply
    77.18x = 115.82 × 31.55
  4. Step 4: Simplify right side
    77.18x = 3,654.12
  5. Step 5: Solve for x
    x = 3,654.12/77.18
  6. Step 6: Final answer
    x = 47.35

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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.