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Finding the Fourth Proportional to 259.80, 389.43 and 198.78

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Solution

The fourth proportional to 259.80, 389.43 and 198.78 is: 297.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.80 : 389.43 = 198.78 : x
  2. Step 2: Convert to fraction form
    259.80/389.43 = 198.78/x
  3. Step 3: Cross multiply
    259.80x = 389.43 × 198.78
  4. Step 4: Simplify right side
    259.80x = 77,410.90
  5. Step 5: Solve for x
    x = 77,410.90/259.80
  6. Step 6: Final answer
    x = 297.96

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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.