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Finding the Fourth Proportional to 518.71, 778.04 and 128.71

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Solution

The fourth proportional to 518.71, 778.04 and 128.71 is: 193.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.71 : 778.04 = 128.71 : x
  2. Step 2: Convert to fraction form
    518.71/778.04 = 128.71/x
  3. Step 3: Cross multiply
    518.71x = 778.04 × 128.71
  4. Step 4: Simplify right side
    518.71x = 100,141.79
  5. Step 5: Solve for x
    x = 100,141.79/518.71
  6. Step 6: Final answer
    x = 193.06

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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.