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Finding the Fourth Proportional to 82.41, 123.81 and 78.31

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Solution

The fourth proportional to 82.41, 123.81 and 78.31 is: 117.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.41 : 123.81 = 78.31 : x
  2. Step 2: Convert to fraction form
    82.41/123.81 = 78.31/x
  3. Step 3: Cross multiply
    82.41x = 123.81 × 78.31
  4. Step 4: Simplify right side
    82.41x = 9,695.56
  5. Step 5: Solve for x
    x = 9,695.56/82.41
  6. Step 6: Final answer
    x = 117.65

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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.