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Finding the Fourth Proportional to 136.39, 204.45 and 78.61

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Solution

The fourth proportional to 136.39, 204.45 and 78.61 is: 117.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.39 : 204.45 = 78.61 : x
  2. Step 2: Convert to fraction form
    136.39/204.45 = 78.61/x
  3. Step 3: Cross multiply
    136.39x = 204.45 × 78.61
  4. Step 4: Simplify right side
    136.39x = 16,071.81
  5. Step 5: Solve for x
    x = 16,071.81/136.39
  6. Step 6: Final answer
    x = 117.84

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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.