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Finding the Fourth Proportional to 139.42, 209.21 and 57.14

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Solution

The fourth proportional to 139.42, 209.21 and 57.14 is: 85.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.42 : 209.21 = 57.14 : x
  2. Step 2: Convert to fraction form
    139.42/209.21 = 57.14/x
  3. Step 3: Cross multiply
    139.42x = 209.21 × 57.14
  4. Step 4: Simplify right side
    139.42x = 11,952.93
  5. Step 5: Solve for x
    x = 11,952.93/139.42
  6. Step 6: Final answer
    x = 85.74

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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.