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Finding the Fourth Proportional to 639.19, 882.10 and 390.48

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Solution

The fourth proportional to 639.19, 882.10 and 390.48 is: 538.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.19 : 882.10 = 390.48 : x
  2. Step 2: Convert to fraction form
    639.19/882.10 = 390.48/x
  3. Step 3: Cross multiply
    639.19x = 882.10 × 390.48
  4. Step 4: Simplify right side
    639.19x = 344,440.97
  5. Step 5: Solve for x
    x = 344,440.97/639.19
  6. Step 6: Final answer
    x = 538.87

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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.