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Finding the Fourth Proportional to 139.21, 191.63 and 120.71

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Solution

The fourth proportional to 139.21, 191.63 and 120.71 is: 166.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.21 : 191.63 = 120.71 : x
  2. Step 2: Convert to fraction form
    139.21/191.63 = 120.71/x
  3. Step 3: Cross multiply
    139.21x = 191.63 × 120.71
  4. Step 4: Simplify right side
    139.21x = 23,132.44
  5. Step 5: Solve for x
    x = 23,132.44/139.21
  6. Step 6: Final answer
    x = 166.17

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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.