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Finding the Fourth Proportional to 139.71, 208.42 and 129.89

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Solution

The fourth proportional to 139.71, 208.42 and 129.89 is: 193.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.71 : 208.42 = 129.89 : x
  2. Step 2: Convert to fraction form
    139.71/208.42 = 129.89/x
  3. Step 3: Cross multiply
    139.71x = 208.42 × 129.89
  4. Step 4: Simplify right side
    139.71x = 27,071.67
  5. Step 5: Solve for x
    x = 27,071.67/139.71
  6. Step 6: Final answer
    x = 193.77

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.