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Finding the Fourth Proportional to 81.51, 112.42 and 77.49

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Solution

The fourth proportional to 81.51, 112.42 and 77.49 is: 106.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.51 : 112.42 = 77.49 : x
  2. Step 2: Convert to fraction form
    81.51/112.42 = 77.49/x
  3. Step 3: Cross multiply
    81.51x = 112.42 × 77.49
  4. Step 4: Simplify right side
    81.51x = 8,711.52
  5. Step 5: Solve for x
    x = 8,711.52/81.51
  6. Step 6: Final answer
    x = 106.88

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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.