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Finding the Fourth Proportional to 639.34, 959.30 and 379.85

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Solution

The fourth proportional to 639.34, 959.30 and 379.85 is: 569.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.34 : 959.30 = 379.85 : x
  2. Step 2: Convert to fraction form
    639.34/959.30 = 379.85/x
  3. Step 3: Cross multiply
    639.34x = 959.30 × 379.85
  4. Step 4: Simplify right side
    639.34x = 364,390.11
  5. Step 5: Solve for x
    x = 364,390.11/639.34
  6. Step 6: Final answer
    x = 569.95

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.