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Finding the Fourth Proportional to 138.51, 189.98 and 122.11

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Solution

The fourth proportional to 138.51, 189.98 and 122.11 is: 167.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.51 : 189.98 = 122.11 : x
  2. Step 2: Convert to fraction form
    138.51/189.98 = 122.11/x
  3. Step 3: Cross multiply
    138.51x = 189.98 × 122.11
  4. Step 4: Simplify right side
    138.51x = 23,198.46
  5. Step 5: Solve for x
    x = 23,198.46/138.51
  6. Step 6: Final answer
    x = 167.49

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.