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Finding the Fourth Proportional to 518.90, 778.20 and 189.80

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Solution

The fourth proportional to 518.90, 778.20 and 189.80 is: 284.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.90 : 778.20 = 189.80 : x
  2. Step 2: Convert to fraction form
    518.90/778.20 = 189.80/x
  3. Step 3: Cross multiply
    518.90x = 778.20 × 189.80
  4. Step 4: Simplify right side
    518.90x = 147,704.31
  5. Step 5: Solve for x
    x = 147,704.31/518.90
  6. Step 6: Final answer
    x = 284.65

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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.