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Finding the Fourth Proportional to 126.44, 189.56 and 80.78

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Solution

The fourth proportional to 126.44, 189.56 and 80.78 is: 121.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.44 : 189.56 = 80.78 : x
  2. Step 2: Convert to fraction form
    126.44/189.56 = 80.78/x
  3. Step 3: Cross multiply
    126.44x = 189.56 × 80.78
  4. Step 4: Simplify right side
    126.44x = 15,312.66
  5. Step 5: Solve for x
    x = 15,312.66/126.44
  6. Step 6: Final answer
    x = 121.11

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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.