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Finding the Fourth Proportional to 81.60, 123.06 and 81.18

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Solution

The fourth proportional to 81.60, 123.06 and 81.18 is: 122.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.60 : 123.06 = 81.18 : x
  2. Step 2: Convert to fraction form
    81.60/123.06 = 81.18/x
  3. Step 3: Cross multiply
    81.60x = 123.06 × 81.18
  4. Step 4: Simplify right side
    81.60x = 9,990.01
  5. Step 5: Solve for x
    x = 9,990.01/81.60
  6. Step 6: Final answer
    x = 122.43

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.