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Finding the Fourth Proportional to 137.74, 206.59 and 79.78

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Solution

The fourth proportional to 137.74, 206.59 and 79.78 is: 119.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.74 : 206.59 = 79.78 : x
  2. Step 2: Convert to fraction form
    137.74/206.59 = 79.78/x
  3. Step 3: Cross multiply
    137.74x = 206.59 × 79.78
  4. Step 4: Simplify right side
    137.74x = 16,481.75
  5. Step 5: Solve for x
    x = 16,481.75/137.74
  6. Step 6: Final answer
    x = 119.66

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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.