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Finding the Fourth Proportional to 82.56, 123 and 80.40

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Solution

The fourth proportional to 82.56, 123 and 80.40 is: 119.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.56 : 123 = 80.40 : x
  2. Step 2: Convert to fraction form
    82.56/123 = 80.40/x
  3. Step 3: Cross multiply
    82.56x = 123 × 80.40
  4. Step 4: Simplify right side
    82.56x = 9,889.20
  5. Step 5: Solve for x
    x = 9,889.20/82.56
  6. Step 6: Final answer
    x = 119.78

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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.