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Finding the Fourth Proportional to 81.38, 112.50 and 77.98

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Solution

The fourth proportional to 81.38, 112.50 and 77.98 is: 107.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.38 : 112.50 = 77.98 : x
  2. Step 2: Convert to fraction form
    81.38/112.50 = 77.98/x
  3. Step 3: Cross multiply
    81.38x = 112.50 × 77.98
  4. Step 4: Simplify right side
    81.38x = 8,772.75
  5. Step 5: Solve for x
    x = 8,772.75/81.38
  6. Step 6: Final answer
    x = 107.80

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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.