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Finding the Fourth Proportional to 640.95, 961.26 and 406.61

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Solution

The fourth proportional to 640.95, 961.26 and 406.61 is: 609.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.95 : 961.26 = 406.61 : x
  2. Step 2: Convert to fraction form
    640.95/961.26 = 406.61/x
  3. Step 3: Cross multiply
    640.95x = 961.26 × 406.61
  4. Step 4: Simplify right side
    640.95x = 390,853.12
  5. Step 5: Solve for x
    x = 390,853.12/640.95
  6. Step 6: Final answer
    x = 609.80

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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.