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Finding the Fourth Proportional to 640.56, 960.70 and 408.72

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Solution

The fourth proportional to 640.56, 960.70 and 408.72 is: 612.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.56 : 960.70 = 408.72 : x
  2. Step 2: Convert to fraction form
    640.56/960.70 = 408.72/x
  3. Step 3: Cross multiply
    640.56x = 960.70 × 408.72
  4. Step 4: Simplify right side
    640.56x = 392,657.30
  5. Step 5: Solve for x
    x = 392,657.30/640.56
  6. Step 6: Final answer
    x = 612.99

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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.