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Finding the Fourth Proportional to 138.32, 190.84 and 79.28

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Solution

The fourth proportional to 138.32, 190.84 and 79.28 is: 109.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.32 : 190.84 = 79.28 : x
  2. Step 2: Convert to fraction form
    138.32/190.84 = 79.28/x
  3. Step 3: Cross multiply
    138.32x = 190.84 × 79.28
  4. Step 4: Simplify right side
    138.32x = 15,129.80
  5. Step 5: Solve for x
    x = 15,129.80/138.32
  6. Step 6: Final answer
    x = 109.38

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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.