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Finding the Fourth Proportional to 81.68, 121.98 and 55.76

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Solution

The fourth proportional to 81.68, 121.98 and 55.76 is: 83.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.68 : 121.98 = 55.76 : x
  2. Step 2: Convert to fraction form
    81.68/121.98 = 55.76/x
  3. Step 3: Cross multiply
    81.68x = 121.98 × 55.76
  4. Step 4: Simplify right side
    81.68x = 6,801.60
  5. Step 5: Solve for x
    x = 6,801.60/81.68
  6. Step 6: Final answer
    x = 83.27

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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.