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Finding the Fourth Proportional to 639.68, 959.74 and 331.60

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Solution

The fourth proportional to 639.68, 959.74 and 331.60 is: 497.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.68 : 959.74 = 331.60 : x
  2. Step 2: Convert to fraction form
    639.68/959.74 = 331.60/x
  3. Step 3: Cross multiply
    639.68x = 959.74 × 331.60
  4. Step 4: Simplify right side
    639.68x = 318,249.78
  5. Step 5: Solve for x
    x = 318,249.78/639.68
  6. Step 6: Final answer
    x = 497.51

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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.