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Finding the Fourth Proportional to 639.55, 882.33 and 390.44

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Solution

The fourth proportional to 639.55, 882.33 and 390.44 is: 538.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.55 : 882.33 = 390.44 : x
  2. Step 2: Convert to fraction form
    639.55/882.33 = 390.44/x
  3. Step 3: Cross multiply
    639.55x = 882.33 × 390.44
  4. Step 4: Simplify right side
    639.55x = 344,496.93
  5. Step 5: Solve for x
    x = 344,496.93/639.55
  6. Step 6: Final answer
    x = 538.66

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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.