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Finding the Fourth Proportional to 136.84, 188.79 and 78.61

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Solution

The fourth proportional to 136.84, 188.79 and 78.61 is: 108.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.84 : 188.79 = 78.61 : x
  2. Step 2: Convert to fraction form
    136.84/188.79 = 78.61/x
  3. Step 3: Cross multiply
    136.84x = 188.79 × 78.61
  4. Step 4: Simplify right side
    136.84x = 14,840.78
  5. Step 5: Solve for x
    x = 14,840.78/136.84
  6. Step 6: Final answer
    x = 108.45

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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.