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Finding the Fourth Proportional to 138.74, 191.46 and 79.70

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Solution

The fourth proportional to 138.74, 191.46 and 79.70 is: 109.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.74 : 191.46 = 79.70 : x
  2. Step 2: Convert to fraction form
    138.74/191.46 = 79.70/x
  3. Step 3: Cross multiply
    138.74x = 191.46 × 79.70
  4. Step 4: Simplify right side
    138.74x = 15,259.36
  5. Step 5: Solve for x
    x = 15,259.36/138.74
  6. Step 6: Final answer
    x = 109.99

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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.