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Finding the Fourth Proportional to 121.80, 168 and 82.47

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Solution

The fourth proportional to 121.80, 168 and 82.47 is: 113.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.80 : 168 = 82.47 : x
  2. Step 2: Convert to fraction form
    121.80/168 = 82.47/x
  3. Step 3: Cross multiply
    121.80x = 168 × 82.47
  4. Step 4: Simplify right side
    121.80x = 13,854.96
  5. Step 5: Solve for x
    x = 13,854.96/121.80
  6. Step 6: Final answer
    x = 113.75

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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.