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Finding the Fourth Proportional to 81.73, 121.86 and 79.63

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Solution

The fourth proportional to 81.73, 121.86 and 79.63 is: 118.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.73 : 121.86 = 79.63 : x
  2. Step 2: Convert to fraction form
    81.73/121.86 = 79.63/x
  3. Step 3: Cross multiply
    81.73x = 121.86 × 79.63
  4. Step 4: Simplify right side
    81.73x = 9,702.70
  5. Step 5: Solve for x
    x = 9,702.70/81.73
  6. Step 6: Final answer
    x = 118.72

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.