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Finding the Fourth Proportional to 82.70, 123.84 and 80.42

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Solution

The fourth proportional to 82.70, 123.84 and 80.42 is: 120.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.70 : 123.84 = 80.42 : x
  2. Step 2: Convert to fraction form
    82.70/123.84 = 80.42/x
  3. Step 3: Cross multiply
    82.70x = 123.84 × 80.42
  4. Step 4: Simplify right side
    82.70x = 9,959.21
  5. Step 5: Solve for x
    x = 9,959.21/82.70
  6. Step 6: Final answer
    x = 120.43

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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.