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Finding the Fourth Proportional to 208.81, 313.28 and 71.85

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Solution

The fourth proportional to 208.81, 313.28 and 71.85 is: 107.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.81 : 313.28 = 71.85 : x
  2. Step 2: Convert to fraction form
    208.81/313.28 = 71.85/x
  3. Step 3: Cross multiply
    208.81x = 313.28 × 71.85
  4. Step 4: Simplify right side
    208.81x = 22,508.03
  5. Step 5: Solve for x
    x = 22,508.03/208.81
  6. Step 6: Final answer
    x = 107.79

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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.