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Finding the Fourth Proportional to 139.29, 209.08 and 67.21

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Solution

The fourth proportional to 139.29, 209.08 and 67.21 is: 100.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.29 : 209.08 = 67.21 : x
  2. Step 2: Convert to fraction form
    139.29/209.08 = 67.21/x
  3. Step 3: Cross multiply
    139.29x = 209.08 × 67.21
  4. Step 4: Simplify right side
    139.29x = 14,051.93
  5. Step 5: Solve for x
    x = 14,051.93/139.29
  6. Step 6: Final answer
    x = 100.88

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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.