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Finding the Fourth Proportional to 121.92, 168.36 and 78.33

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Solution

The fourth proportional to 121.92, 168.36 and 78.33 is: 108.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.92 : 168.36 = 78.33 : x
  2. Step 2: Convert to fraction form
    121.92/168.36 = 78.33/x
  3. Step 3: Cross multiply
    121.92x = 168.36 × 78.33
  4. Step 4: Simplify right side
    121.92x = 13,187.94
  5. Step 5: Solve for x
    x = 13,187.94/121.92
  6. Step 6: Final answer
    x = 108.17

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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.