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Finding the Fourth Proportional to 139.15, 208.73 and 47.85

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Solution

The fourth proportional to 139.15, 208.73 and 47.85 is: 71.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.15 : 208.73 = 47.85 : x
  2. Step 2: Convert to fraction form
    139.15/208.73 = 47.85/x
  3. Step 3: Cross multiply
    139.15x = 208.73 × 47.85
  4. Step 4: Simplify right side
    139.15x = 9,986.45
  5. Step 5: Solve for x
    x = 9,986.45/139.15
  6. Step 6: Final answer
    x = 71.77

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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.