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Finding the Fourth Proportional to 639.66, 961.30 and 379.71

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Solution

The fourth proportional to 639.66, 961.30 and 379.71 is: 570.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.66 : 961.30 = 379.71 : x
  2. Step 2: Convert to fraction form
    639.66/961.30 = 379.71/x
  3. Step 3: Cross multiply
    639.66x = 961.30 × 379.71
  4. Step 4: Simplify right side
    639.66x = 365,008.52
  5. Step 5: Solve for x
    x = 365,008.52/639.66
  6. Step 6: Final answer
    x = 570.63

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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.