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Finding the Fourth Proportional to 631.92, 872.04 and 399.12

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Solution

The fourth proportional to 631.92, 872.04 and 399.12 is: 550.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    631.92 : 872.04 = 399.12 : x
  2. Step 2: Convert to fraction form
    631.92/872.04 = 399.12/x
  3. Step 3: Cross multiply
    631.92x = 872.04 × 399.12
  4. Step 4: Simplify right side
    631.92x = 348,048.60
  5. Step 5: Solve for x
    x = 348,048.60/631.92
  6. Step 6: Final answer
    x = 550.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.