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Finding the Fourth Proportional to 121.75, 168.15 and 82.87

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Solution

The fourth proportional to 121.75, 168.15 and 82.87 is: 114.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.75 : 168.15 = 82.87 : x
  2. Step 2: Convert to fraction form
    121.75/168.15 = 82.87/x
  3. Step 3: Cross multiply
    121.75x = 168.15 × 82.87
  4. Step 4: Simplify right side
    121.75x = 13,934.59
  5. Step 5: Solve for x
    x = 13,934.59/121.75
  6. Step 6: Final answer
    x = 114.45

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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.