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Finding the Fourth Proportional to 639.90, 958.86 and 423.09

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Solution

The fourth proportional to 639.90, 958.86 and 423.09 is: 633.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.90 : 958.86 = 423.09 : x
  2. Step 2: Convert to fraction form
    639.90/958.86 = 423.09/x
  3. Step 3: Cross multiply
    639.90x = 958.86 × 423.09
  4. Step 4: Simplify right side
    639.90x = 405,684.08
  5. Step 5: Solve for x
    x = 405,684.08/639.90
  6. Step 6: Final answer
    x = 633.98

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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.