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Finding the Fourth Proportional to 139.20, 192.02 and 100.40

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Solution

The fourth proportional to 139.20, 192.02 and 100.40 is: 138.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.20 : 192.02 = 100.40 : x
  2. Step 2: Convert to fraction form
    139.20/192.02 = 100.40/x
  3. Step 3: Cross multiply
    139.20x = 192.02 × 100.40
  4. Step 4: Simplify right side
    139.20x = 19,278.81
  5. Step 5: Solve for x
    x = 19,278.81/139.20
  6. Step 6: Final answer
    x = 138.50

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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.