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Finding the Fourth Proportional to 126.70, 189.81 and 81.07

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Solution

The fourth proportional to 126.70, 189.81 and 81.07 is: 121.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.70 : 189.81 = 81.07 : x
  2. Step 2: Convert to fraction form
    126.70/189.81 = 81.07/x
  3. Step 3: Cross multiply
    126.70x = 189.81 × 81.07
  4. Step 4: Simplify right side
    126.70x = 15,387.42
  5. Step 5: Solve for x
    x = 15,387.42/126.70
  6. Step 6: Final answer
    x = 121.45

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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.