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Finding the Fourth Proportional to 518.30, 779.20 and 287.61

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Solution

The fourth proportional to 518.30, 779.20 and 287.61 is: 432.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.30 : 779.20 = 287.61 : x
  2. Step 2: Convert to fraction form
    518.30/779.20 = 287.61/x
  3. Step 3: Cross multiply
    518.30x = 779.20 × 287.61
  4. Step 4: Simplify right side
    518.30x = 224,103.69
  5. Step 5: Solve for x
    x = 224,103.69/518.30
  6. Step 6: Final answer
    x = 432.38

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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.