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Finding the Fourth Proportional to 209.13, 313.69 and 80.88

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Solution

The fourth proportional to 209.13, 313.69 and 80.88 is: 121.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.13 : 313.69 = 80.88 : x
  2. Step 2: Convert to fraction form
    209.13/313.69 = 80.88/x
  3. Step 3: Cross multiply
    209.13x = 313.69 × 80.88
  4. Step 4: Simplify right side
    209.13x = 25,371.25
  5. Step 5: Solve for x
    x = 25,371.25/209.13
  6. Step 6: Final answer
    x = 121.32

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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.