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Finding the Fourth Proportional to 425.28, 638.16 and 206.42

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Solution

The fourth proportional to 425.28, 638.16 and 206.42 is: 309.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.28 : 638.16 = 206.42 : x
  2. Step 2: Convert to fraction form
    425.28/638.16 = 206.42/x
  3. Step 3: Cross multiply
    425.28x = 638.16 × 206.42
  4. Step 4: Simplify right side
    425.28x = 131,728.99
  5. Step 5: Solve for x
    x = 131,728.99/425.28
  6. Step 6: Final answer
    x = 309.75

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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.