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Finding the Fourth Proportional to 82.42, 122.81 and 78.04

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Solution

The fourth proportional to 82.42, 122.81 and 78.04 is: 116.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.42 : 122.81 = 78.04 : x
  2. Step 2: Convert to fraction form
    82.42/122.81 = 78.04/x
  3. Step 3: Cross multiply
    82.42x = 122.81 × 78.04
  4. Step 4: Simplify right side
    82.42x = 9,584.09
  5. Step 5: Solve for x
    x = 9,584.09/82.42
  6. Step 6: Final answer
    x = 116.28

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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.