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Finding the Fourth Proportional to 126.56, 189.71 and 80.90

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Solution

The fourth proportional to 126.56, 189.71 and 80.90 is: 121.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.56 : 189.71 = 80.90 : x
  2. Step 2: Convert to fraction form
    126.56/189.71 = 80.90/x
  3. Step 3: Cross multiply
    126.56x = 189.71 × 80.90
  4. Step 4: Simplify right side
    126.56x = 15,347.20
  5. Step 5: Solve for x
    x = 15,347.20/126.56
  6. Step 6: Final answer
    x = 121.26

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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.