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Finding the Fourth Proportional to 136.71, 188.66 and 78.49

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Solution

The fourth proportional to 136.71, 188.66 and 78.49 is: 108.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.71 : 188.66 = 78.49 : x
  2. Step 2: Convert to fraction form
    136.71/188.66 = 78.49/x
  3. Step 3: Cross multiply
    136.71x = 188.66 × 78.49
  4. Step 4: Simplify right side
    136.71x = 14,807.92
  5. Step 5: Solve for x
    x = 14,807.92/136.71
  6. Step 6: Final answer
    x = 108.32

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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.