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Finding the Fourth Proportional to 639.84, 882.84 and 391.32

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Solution

The fourth proportional to 639.84, 882.84 and 391.32 is: 539.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.84 : 882.84 = 391.32 : x
  2. Step 2: Convert to fraction form
    639.84/882.84 = 391.32/x
  3. Step 3: Cross multiply
    639.84x = 882.84 × 391.32
  4. Step 4: Simplify right side
    639.84x = 345,472.95
  5. Step 5: Solve for x
    x = 345,472.95/639.84
  6. Step 6: Final answer
    x = 539.94

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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.