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Finding the Fourth Proportional to 139.41, 209 and 85.24

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Solution

The fourth proportional to 139.41, 209 and 85.24 is: 127.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.41 : 209 = 85.24 : x
  2. Step 2: Convert to fraction form
    139.41/209 = 85.24/x
  3. Step 3: Cross multiply
    139.41x = 209 × 85.24
  4. Step 4: Simplify right side
    139.41x = 17,815.16
  5. Step 5: Solve for x
    x = 17,815.16/139.41
  6. Step 6: Final answer
    x = 127.79

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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.