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Finding the Fourth Proportional to 1,679.82, 2,520.85 and 640.78

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Solution

The fourth proportional to 1,679.82, 2,520.85 and 640.78 is: 961.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,679.82 : 2,520.85 = 640.78 : x
  2. Step 2: Convert to fraction form
    1,679.82/2,520.85 = 640.78/x
  3. Step 3: Cross multiply
    1,679.82x = 2,520.85 × 640.78
  4. Step 4: Simplify right side
    1,679.82x = 1,615,310.26
  5. Step 5: Solve for x
    x = 1,615,310.26/1,679.82
  6. Step 6: Final answer
    x = 961.60

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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.