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Finding the Fourth Proportional to 139.21, 208.84 and 47.91

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Solution

The fourth proportional to 139.21, 208.84 and 47.91 is: 71.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.21 : 208.84 = 47.91 : x
  2. Step 2: Convert to fraction form
    139.21/208.84 = 47.91/x
  3. Step 3: Cross multiply
    139.21x = 208.84 × 47.91
  4. Step 4: Simplify right side
    139.21x = 10,005.10
  5. Step 5: Solve for x
    x = 10,005.10/139.21
  6. Step 6: Final answer
    x = 71.87

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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.