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Finding the Fourth Proportional to 426.25, 639.15 and 206.80

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Solution

The fourth proportional to 426.25, 639.15 and 206.80 is: 310.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.25 : 639.15 = 206.80 : x
  2. Step 2: Convert to fraction form
    426.25/639.15 = 206.80/x
  3. Step 3: Cross multiply
    426.25x = 639.15 × 206.80
  4. Step 4: Simplify right side
    426.25x = 132,176.22
  5. Step 5: Solve for x
    x = 132,176.22/426.25
  6. Step 6: Final answer
    x = 310.09

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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.