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Finding the Fourth Proportional to 664.84, 996.18 and 420.40

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Solution

The fourth proportional to 664.84, 996.18 and 420.40 is: 629.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.84 : 996.18 = 420.40 : x
  2. Step 2: Convert to fraction form
    664.84/996.18 = 420.40/x
  3. Step 3: Cross multiply
    664.84x = 996.18 × 420.40
  4. Step 4: Simplify right side
    664.84x = 418,794.07
  5. Step 5: Solve for x
    x = 418,794.07/664.84
  6. Step 6: Final answer
    x = 629.92

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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.