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Finding the Fourth Proportional to 208.72, 313.20 and 80.56

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Solution

The fourth proportional to 208.72, 313.20 and 80.56 is: 120.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.72 : 313.20 = 80.56 : x
  2. Step 2: Convert to fraction form
    208.72/313.20 = 80.56/x
  3. Step 3: Cross multiply
    208.72x = 313.20 × 80.56
  4. Step 4: Simplify right side
    208.72x = 25,231.39
  5. Step 5: Solve for x
    x = 25,231.39/208.72
  6. Step 6: Final answer
    x = 120.89

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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.