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Finding the Fourth Proportional to 82.56, 123.84 and 81.12

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Solution

The fourth proportional to 82.56, 123.84 and 81.12 is: 121.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.56 : 123.84 = 81.12 : x
  2. Step 2: Convert to fraction form
    82.56/123.84 = 81.12/x
  3. Step 3: Cross multiply
    82.56x = 123.84 × 81.12
  4. Step 4: Simplify right side
    82.56x = 10,045.90
  5. Step 5: Solve for x
    x = 10,045.90/82.56
  6. Step 6: Final answer
    x = 121.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.