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Finding the Fourth Proportional to 126.79, 190.25 and 81.16

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Solution

The fourth proportional to 126.79, 190.25 and 81.16 is: 121.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.79 : 190.25 = 81.16 : x
  2. Step 2: Convert to fraction form
    126.79/190.25 = 81.16/x
  3. Step 3: Cross multiply
    126.79x = 190.25 × 81.16
  4. Step 4: Simplify right side
    126.79x = 15,440.69
  5. Step 5: Solve for x
    x = 15,440.69/126.79
  6. Step 6: Final answer
    x = 121.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.