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Finding the Fourth Proportional to 639.14, 881.89 and 390.52

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Solution

The fourth proportional to 639.14, 881.89 and 390.52 is: 538.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.14 : 881.89 = 390.52 : x
  2. Step 2: Convert to fraction form
    639.14/881.89 = 390.52/x
  3. Step 3: Cross multiply
    639.14x = 881.89 × 390.52
  4. Step 4: Simplify right side
    639.14x = 344,389.32
  5. Step 5: Solve for x
    x = 344,389.32/639.14
  6. Step 6: Final answer
    x = 538.84

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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.