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Finding the Fourth Proportional to 641.20, 961.80 and 208.36

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Solution

The fourth proportional to 641.20, 961.80 and 208.36 is: 312.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.20 : 961.80 = 208.36 : x
  2. Step 2: Convert to fraction form
    641.20/961.80 = 208.36/x
  3. Step 3: Cross multiply
    641.20x = 961.80 × 208.36
  4. Step 4: Simplify right side
    641.20x = 200,400.65
  5. Step 5: Solve for x
    x = 200,400.65/641.20
  6. Step 6: Final answer
    x = 312.54

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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.