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Finding the Fourth Proportional to 126.21, 189.42 and 54.12

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Solution

The fourth proportional to 126.21, 189.42 and 54.12 is: 81.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.21 : 189.42 = 54.12 : x
  2. Step 2: Convert to fraction form
    126.21/189.42 = 54.12/x
  3. Step 3: Cross multiply
    126.21x = 189.42 × 54.12
  4. Step 4: Simplify right side
    126.21x = 10,251.41
  5. Step 5: Solve for x
    x = 10,251.41/126.21
  6. Step 6: Final answer
    x = 81.23

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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.