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Finding the Fourth Proportional to 136.76, 188.74 and 78.56

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Solution

The fourth proportional to 136.76, 188.74 and 78.56 is: 108.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.76 : 188.74 = 78.56 : x
  2. Step 2: Convert to fraction form
    136.76/188.74 = 78.56/x
  3. Step 3: Cross multiply
    136.76x = 188.74 × 78.56
  4. Step 4: Simplify right side
    136.76x = 14,827.41
  5. Step 5: Solve for x
    x = 14,827.41/136.76
  6. Step 6: Final answer
    x = 108.42

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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.