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Finding the Fourth Proportional to 641.45, 961.86 and 208.55

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Solution

The fourth proportional to 641.45, 961.86 and 208.55 is: 312.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.45 : 961.86 = 208.55 : x
  2. Step 2: Convert to fraction form
    641.45/961.86 = 208.55/x
  3. Step 3: Cross multiply
    641.45x = 961.86 × 208.55
  4. Step 4: Simplify right side
    641.45x = 200,595.90
  5. Step 5: Solve for x
    x = 200,595.90/641.45
  6. Step 6: Final answer
    x = 312.72

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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.