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Finding the Fourth Proportional to 138.65, 191.84 and 116.78

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Solution

The fourth proportional to 138.65, 191.84 and 116.78 is: 161.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.65 : 191.84 = 116.78 : x
  2. Step 2: Convert to fraction form
    138.65/191.84 = 116.78/x
  3. Step 3: Cross multiply
    138.65x = 191.84 × 116.78
  4. Step 4: Simplify right side
    138.65x = 22,401.53
  5. Step 5: Solve for x
    x = 22,401.53/138.65
  6. Step 6: Final answer
    x = 161.57

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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.