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Finding the Fourth Proportional to 139.49, 209.31 and 57.23

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Solution

The fourth proportional to 139.49, 209.31 and 57.23 is: 85.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.49 : 209.31 = 57.23 : x
  2. Step 2: Convert to fraction form
    139.49/209.31 = 57.23/x
  3. Step 3: Cross multiply
    139.49x = 209.31 × 57.23
  4. Step 4: Simplify right side
    139.49x = 11,978.53
  5. Step 5: Solve for x
    x = 11,978.53/139.49
  6. Step 6: Final answer
    x = 85.88

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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.