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Finding the Fourth Proportional to 136.83, 188.78 and 87.69

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Solution

The fourth proportional to 136.83, 188.78 and 87.69 is: 120.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.83 : 188.78 = 87.69 : x
  2. Step 2: Convert to fraction form
    136.83/188.78 = 87.69/x
  3. Step 3: Cross multiply
    136.83x = 188.78 × 87.69
  4. Step 4: Simplify right side
    136.83x = 16,553.68
  5. Step 5: Solve for x
    x = 16,553.68/136.83
  6. Step 6: Final answer
    x = 120.98

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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.