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Finding the Fourth Proportional to 138.26, 190.88 and 91.70

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Solution

The fourth proportional to 138.26, 190.88 and 91.70 is: 126.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.26 : 190.88 = 91.70 : x
  2. Step 2: Convert to fraction form
    138.26/190.88 = 91.70/x
  3. Step 3: Cross multiply
    138.26x = 190.88 × 91.70
  4. Step 4: Simplify right side
    138.26x = 17,503.87
  5. Step 5: Solve for x
    x = 17,503.87/138.26
  6. Step 6: Final answer
    x = 126.60

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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.