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Finding the Fourth Proportional to 138.23, 190.74 and 80

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Solution

The fourth proportional to 138.23, 190.74 and 80 is: 110.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.23 : 190.74 = 80 : x
  2. Step 2: Convert to fraction form
    138.23/190.74 = 80/x
  3. Step 3: Cross multiply
    138.23x = 190.74 × 80
  4. Step 4: Simplify right side
    138.23x = 15,259.20
  5. Step 5: Solve for x
    x = 15,259.20/138.23
  6. Step 6: Final answer
    x = 110.39

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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.