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Finding the Fourth Proportional to 136.96, 189.01 and 78.74

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Solution

The fourth proportional to 136.96, 189.01 and 78.74 is: 108.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.96 : 189.01 = 78.74 : x
  2. Step 2: Convert to fraction form
    136.96/189.01 = 78.74/x
  3. Step 3: Cross multiply
    136.96x = 189.01 × 78.74
  4. Step 4: Simplify right side
    136.96x = 14,882.29
  5. Step 5: Solve for x
    x = 14,882.29/136.96
  6. Step 6: Final answer
    x = 108.66

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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.