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Finding the Fourth Proportional to 138.51, 191.18 and 79.51

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Solution

The fourth proportional to 138.51, 191.18 and 79.51 is: 109.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.51 : 191.18 = 79.51 : x
  2. Step 2: Convert to fraction form
    138.51/191.18 = 79.51/x
  3. Step 3: Cross multiply
    138.51x = 191.18 × 79.51
  4. Step 4: Simplify right side
    138.51x = 15,200.68
  5. Step 5: Solve for x
    x = 15,200.68/138.51
  6. Step 6: Final answer
    x = 109.74

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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.