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Finding the Fourth Proportional to 638.79, 881.57 and 355.22

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Solution

The fourth proportional to 638.79, 881.57 and 355.22 is: 490.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.79 : 881.57 = 355.22 : x
  2. Step 2: Convert to fraction form
    638.79/881.57 = 355.22/x
  3. Step 3: Cross multiply
    638.79x = 881.57 × 355.22
  4. Step 4: Simplify right side
    638.79x = 313,151.30
  5. Step 5: Solve for x
    x = 313,151.30/638.79
  6. Step 6: Final answer
    x = 490.23

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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.