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Finding the Fourth Proportional to 121.82, 168.08 and 78.14

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Solution

The fourth proportional to 121.82, 168.08 and 78.14 is: 107.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.82 : 168.08 = 78.14 : x
  2. Step 2: Convert to fraction form
    121.82/168.08 = 78.14/x
  3. Step 3: Cross multiply
    121.82x = 168.08 × 78.14
  4. Step 4: Simplify right side
    121.82x = 13,133.80
  5. Step 5: Solve for x
    x = 13,133.80/121.82
  6. Step 6: Final answer
    x = 107.82

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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.