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Finding the Fourth Proportional to 639.63, 959.43 and 423.15

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Solution

The fourth proportional to 639.63, 959.43 and 423.15 is: 634.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.63 : 959.43 = 423.15 : x
  2. Step 2: Convert to fraction form
    639.63/959.43 = 423.15/x
  3. Step 3: Cross multiply
    639.63x = 959.43 × 423.15
  4. Step 4: Simplify right side
    639.63x = 405,982.80
  5. Step 5: Solve for x
    x = 405,982.80/639.63
  6. Step 6: Final answer
    x = 634.72

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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.