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Finding the Fourth Proportional to 137.72, 190.04 and 78.71

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Solution

The fourth proportional to 137.72, 190.04 and 78.71 is: 108.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.72 : 190.04 = 78.71 : x
  2. Step 2: Convert to fraction form
    137.72/190.04 = 78.71/x
  3. Step 3: Cross multiply
    137.72x = 190.04 × 78.71
  4. Step 4: Simplify right side
    137.72x = 14,958.05
  5. Step 5: Solve for x
    x = 14,958.05/137.72
  6. Step 6: Final answer
    x = 108.61

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.