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Finding the Fourth Proportional to 139.39, 192.36 and 81.19

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Solution

The fourth proportional to 139.39, 192.36 and 81.19 is: 112.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.39 : 192.36 = 81.19 : x
  2. Step 2: Convert to fraction form
    139.39/192.36 = 81.19/x
  3. Step 3: Cross multiply
    139.39x = 192.36 × 81.19
  4. Step 4: Simplify right side
    139.39x = 15,617.71
  5. Step 5: Solve for x
    x = 15,617.71/139.39
  6. Step 6: Final answer
    x = 112.04

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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.