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Finding the Fourth Proportional to 664.36, 996.72 and 420.64

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Solution

The fourth proportional to 664.36, 996.72 and 420.64 is: 631.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.36 : 996.72 = 420.64 : x
  2. Step 2: Convert to fraction form
    664.36/996.72 = 420.64/x
  3. Step 3: Cross multiply
    664.36x = 996.72 × 420.64
  4. Step 4: Simplify right side
    664.36x = 419,260.30
  5. Step 5: Solve for x
    x = 419,260.30/664.36
  6. Step 6: Final answer
    x = 631.07

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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.