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Finding the Fourth Proportional to 641.32, 961.40 and 208.20

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Solution

The fourth proportional to 641.32, 961.40 and 208.20 is: 312.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.32 : 961.40 = 208.20 : x
  2. Step 2: Convert to fraction form
    641.32/961.40 = 208.20/x
  3. Step 3: Cross multiply
    641.32x = 961.40 × 208.20
  4. Step 4: Simplify right side
    641.32x = 200,163.48
  5. Step 5: Solve for x
    x = 200,163.48/641.32
  6. Step 6: Final answer
    x = 312.11

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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.