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Finding the Fourth Proportional to 126.72, 189.78 and 71.79

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Solution

The fourth proportional to 126.72, 189.78 and 71.79 is: 107.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.72 : 189.78 = 71.79 : x
  2. Step 2: Convert to fraction form
    126.72/189.78 = 71.79/x
  3. Step 3: Cross multiply
    126.72x = 189.78 × 71.79
  4. Step 4: Simplify right side
    126.72x = 13,624.39
  5. Step 5: Solve for x
    x = 13,624.39/126.72
  6. Step 6: Final answer
    x = 107.52

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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.