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Finding the Fourth Proportional to 82.33, 122.56 and 78.40

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Solution

The fourth proportional to 82.33, 122.56 and 78.40 is: 116.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.33 : 122.56 = 78.40 : x
  2. Step 2: Convert to fraction form
    82.33/122.56 = 78.40/x
  3. Step 3: Cross multiply
    82.33x = 122.56 × 78.40
  4. Step 4: Simplify right side
    82.33x = 9,608.70
  5. Step 5: Solve for x
    x = 9,608.70/82.33
  6. Step 6: Final answer
    x = 116.71

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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.