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Finding the Fourth Proportional to 426.21, 639.41 and 137.63

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Solution

The fourth proportional to 426.21, 639.41 and 137.63 is: 206.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.21 : 639.41 = 137.63 : x
  2. Step 2: Convert to fraction form
    426.21/639.41 = 137.63/x
  3. Step 3: Cross multiply
    426.21x = 639.41 × 137.63
  4. Step 4: Simplify right side
    426.21x = 87,998.11
  5. Step 5: Solve for x
    x = 87,998.11/426.21
  6. Step 6: Final answer
    x = 206.47

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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.