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Finding the Fourth Proportional to 640.80, 961.12 and 207.92

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Solution

The fourth proportional to 640.80, 961.12 and 207.92 is: 311.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.80 : 961.12 = 207.92 : x
  2. Step 2: Convert to fraction form
    640.80/961.12 = 207.92/x
  3. Step 3: Cross multiply
    640.80x = 961.12 × 207.92
  4. Step 4: Simplify right side
    640.80x = 199,836.07
  5. Step 5: Solve for x
    x = 199,836.07/640.80
  6. Step 6: Final answer
    x = 311.85

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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.