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Finding the Fourth Proportional to 139.40, 192.41 and 81.23

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Solution

The fourth proportional to 139.40, 192.41 and 81.23 is: 112.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.40 : 192.41 = 81.23 : x
  2. Step 2: Convert to fraction form
    139.40/192.41 = 81.23/x
  3. Step 3: Cross multiply
    139.40x = 192.41 × 81.23
  4. Step 4: Simplify right side
    139.40x = 15,628.71
  5. Step 5: Solve for x
    x = 15,628.71/139.40
  6. Step 6: Final answer
    x = 112.12

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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.