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Finding the Fourth Proportional to 138.78, 190.89 and 126.63

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Solution

The fourth proportional to 138.78, 190.89 and 126.63 is: 174.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.78 : 190.89 = 126.63 : x
  2. Step 2: Convert to fraction form
    138.78/190.89 = 126.63/x
  3. Step 3: Cross multiply
    138.78x = 190.89 × 126.63
  4. Step 4: Simplify right side
    138.78x = 24,172.40
  5. Step 5: Solve for x
    x = 24,172.40/138.78
  6. Step 6: Final answer
    x = 174.18

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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.