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Finding the Fourth Proportional to 639.77, 882.87 and 391.51

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Solution

The fourth proportional to 639.77, 882.87 and 391.51 is: 540.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.77 : 882.87 = 391.51 : x
  2. Step 2: Convert to fraction form
    639.77/882.87 = 391.51/x
  3. Step 3: Cross multiply
    639.77x = 882.87 × 391.51
  4. Step 4: Simplify right side
    639.77x = 345,650.23
  5. Step 5: Solve for x
    x = 345,650.23/639.77
  6. Step 6: Final answer
    x = 540.27

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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.