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Finding the Fourth Proportional to 121.70, 168.03 and 86.47

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Solution

The fourth proportional to 121.70, 168.03 and 86.47 is: 119.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.70 : 168.03 = 86.47 : x
  2. Step 2: Convert to fraction form
    121.70/168.03 = 86.47/x
  3. Step 3: Cross multiply
    121.70x = 168.03 × 86.47
  4. Step 4: Simplify right side
    121.70x = 14,529.13
  5. Step 5: Solve for x
    x = 14,529.13/121.70
  6. Step 6: Final answer
    x = 119.38

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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.