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Finding the Fourth Proportional to 138.58, 191.41 and 121.06

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Solution

The fourth proportional to 138.58, 191.41 and 121.06 is: 167.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.58 : 191.41 = 121.06 : x
  2. Step 2: Convert to fraction form
    138.58/191.41 = 121.06/x
  3. Step 3: Cross multiply
    138.58x = 191.41 × 121.06
  4. Step 4: Simplify right side
    138.58x = 23,172.09
  5. Step 5: Solve for x
    x = 23,172.09/138.58
  6. Step 6: Final answer
    x = 167.21

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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.