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Finding the Fourth Proportional to 139.92, 193.31 and 128.99

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Solution

The fourth proportional to 139.92, 193.31 and 128.99 is: 178.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.92 : 193.31 = 128.99 : x
  2. Step 2: Convert to fraction form
    139.92/193.31 = 128.99/x
  3. Step 3: Cross multiply
    139.92x = 193.31 × 128.99
  4. Step 4: Simplify right side
    139.92x = 24,933.45
  5. Step 5: Solve for x
    x = 24,933.45/139.92
  6. Step 6: Final answer
    x = 178.20

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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.