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Finding the Fourth Proportional to 639.02, 881.82 and 390.75

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Solution

The fourth proportional to 639.02, 881.82 and 390.75 is: 539.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.02 : 881.82 = 390.75 : x
  2. Step 2: Convert to fraction form
    639.02/881.82 = 390.75/x
  3. Step 3: Cross multiply
    639.02x = 881.82 × 390.75
  4. Step 4: Simplify right side
    639.02x = 344,571.17
  5. Step 5: Solve for x
    x = 344,571.17/639.02
  6. Step 6: Final answer
    x = 539.22

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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.