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Finding the Fourth Proportional to 638.88, 881.63 and 399.56

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Solution

The fourth proportional to 638.88, 881.63 and 399.56 is: 551.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.88 : 881.63 = 399.56 : x
  2. Step 2: Convert to fraction form
    638.88/881.63 = 399.56/x
  3. Step 3: Cross multiply
    638.88x = 881.63 × 399.56
  4. Step 4: Simplify right side
    638.88x = 352,264.08
  5. Step 5: Solve for x
    x = 352,264.08/638.88
  6. Step 6: Final answer
    x = 551.38

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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.