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Finding the Fourth Proportional to 639.03, 881.94 and 390.30

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Solution

The fourth proportional to 639.03, 881.94 and 390.30 is: 538.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.03 : 881.94 = 390.30 : x
  2. Step 2: Convert to fraction form
    639.03/881.94 = 390.30/x
  3. Step 3: Cross multiply
    639.03x = 881.94 × 390.30
  4. Step 4: Simplify right side
    639.03x = 344,216.77
  5. Step 5: Solve for x
    x = 344,216.77/639.03
  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.