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Finding the Fourth Proportional to 640.25, 959.72 and 409.40

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Solution

The fourth proportional to 640.25, 959.72 and 409.40 is: 613.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.25 : 959.72 = 409.40 : x
  2. Step 2: Convert to fraction form
    640.25/959.72 = 409.40/x
  3. Step 3: Cross multiply
    640.25x = 959.72 × 409.40
  4. Step 4: Simplify right side
    640.25x = 392,905.59
  5. Step 5: Solve for x
    x = 392,905.59/640.25
  6. Step 6: Final answer
    x = 613.68

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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.