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Finding the Fourth Proportional to 81.57, 112.41 and 79.77

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Solution

The fourth proportional to 81.57, 112.41 and 79.77 is: 109.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.57 : 112.41 = 79.77 : x
  2. Step 2: Convert to fraction form
    81.57/112.41 = 79.77/x
  3. Step 3: Cross multiply
    81.57x = 112.41 × 79.77
  4. Step 4: Simplify right side
    81.57x = 8,966.95
  5. Step 5: Solve for x
    x = 8,966.95/81.57
  6. Step 6: Final answer
    x = 109.93

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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.