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Finding the Fourth Proportional to 138.99, 191.74 and 80.74

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Solution

The fourth proportional to 138.99, 191.74 and 80.74 is: 111.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.99 : 191.74 = 80.74 : x
  2. Step 2: Convert to fraction form
    138.99/191.74 = 80.74/x
  3. Step 3: Cross multiply
    138.99x = 191.74 × 80.74
  4. Step 4: Simplify right side
    138.99x = 15,479.93
  5. Step 5: Solve for x
    x = 15,479.93/138.99
  6. Step 6: Final answer
    x = 111.38

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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.