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Finding the Fourth Proportional to 139.15, 208.77 and 47.91

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Solution

The fourth proportional to 139.15, 208.77 and 47.91 is: 71.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.15 : 208.77 = 47.91 : x
  2. Step 2: Convert to fraction form
    139.15/208.77 = 47.91/x
  3. Step 3: Cross multiply
    139.15x = 208.77 × 47.91
  4. Step 4: Simplify right side
    139.15x = 10,002.17
  5. Step 5: Solve for x
    x = 10,002.17/139.15
  6. Step 6: Final answer
    x = 71.88

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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.