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Finding the Fourth Proportional to 139.68, 192.88 and 102.90

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Solution

The fourth proportional to 139.68, 192.88 and 102.90 is: 142.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.68 : 192.88 = 102.90 : x
  2. Step 2: Convert to fraction form
    139.68/192.88 = 102.90/x
  3. Step 3: Cross multiply
    139.68x = 192.88 × 102.90
  4. Step 4: Simplify right side
    139.68x = 19,847.35
  5. Step 5: Solve for x
    x = 19,847.35/139.68
  6. Step 6: Final answer
    x = 142.09

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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.