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Finding the Fourth Proportional to 639.68, 883.26 and 391.12

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Solution

The fourth proportional to 639.68, 883.26 and 391.12 is: 540.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.68 : 883.26 = 391.12 : x
  2. Step 2: Convert to fraction form
    639.68/883.26 = 391.12/x
  3. Step 3: Cross multiply
    639.68x = 883.26 × 391.12
  4. Step 4: Simplify right side
    639.68x = 345,458.44
  5. Step 5: Solve for x
    x = 345,458.44/639.68
  6. Step 6: Final answer
    x = 540.05

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.