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Finding the Fourth Proportional to 139.53, 209.33 and 57.21

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Solution

The fourth proportional to 139.53, 209.33 and 57.21 is: 85.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.53 : 209.33 = 57.21 : x
  2. Step 2: Convert to fraction form
    139.53/209.33 = 57.21/x
  3. Step 3: Cross multiply
    139.53x = 209.33 × 57.21
  4. Step 4: Simplify right side
    139.53x = 11,975.77
  5. Step 5: Solve for x
    x = 11,975.77/139.53
  6. Step 6: Final answer
    x = 85.83

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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.