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Finding the Fourth Proportional to 641.15, 961.86 and 208.61

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Solution

The fourth proportional to 641.15, 961.86 and 208.61 is: 312.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.15 : 961.86 = 208.61 : x
  2. Step 2: Convert to fraction form
    641.15/961.86 = 208.61/x
  3. Step 3: Cross multiply
    641.15x = 961.86 × 208.61
  4. Step 4: Simplify right side
    641.15x = 200,652.02
  5. Step 5: Solve for x
    x = 200,652.02/641.15
  6. Step 6: Final answer
    x = 312.96

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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.