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Finding the Fourth Proportional to 121.84, 168.03 and 78.19

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Solution

The fourth proportional to 121.84, 168.03 and 78.19 is: 107.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.84 : 168.03 = 78.19 : x
  2. Step 2: Convert to fraction form
    121.84/168.03 = 78.19/x
  3. Step 3: Cross multiply
    121.84x = 168.03 × 78.19
  4. Step 4: Simplify right side
    121.84x = 13,138.27
  5. Step 5: Solve for x
    x = 13,138.27/121.84
  6. Step 6: Final answer
    x = 107.83

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.