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Finding the Fourth Proportional to 139.89, 209.85 and 79.14

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Solution

The fourth proportional to 139.89, 209.85 and 79.14 is: 118.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.89 : 209.85 = 79.14 : x
  2. Step 2: Convert to fraction form
    139.89/209.85 = 79.14/x
  3. Step 3: Cross multiply
    139.89x = 209.85 × 79.14
  4. Step 4: Simplify right side
    139.89x = 16,607.53
  5. Step 5: Solve for x
    x = 16,607.53/139.89
  6. Step 6: Final answer
    x = 118.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.