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Finding the Fourth Proportional to 138.51, 190.98 and 91.85

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Solution

The fourth proportional to 138.51, 190.98 and 91.85 is: 126.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.51 : 190.98 = 91.85 : x
  2. Step 2: Convert to fraction form
    138.51/190.98 = 91.85/x
  3. Step 3: Cross multiply
    138.51x = 190.98 × 91.85
  4. Step 4: Simplify right side
    138.51x = 17,540.56
  5. Step 5: Solve for x
    x = 17,540.56/138.51
  6. Step 6: Final answer
    x = 126.64

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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.