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Finding the Fourth Proportional to 839.85, 1,259.90 and 254.78

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Solution

The fourth proportional to 839.85, 1,259.90 and 254.78 is: 382.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.85 : 1,259.90 = 254.78 : x
  2. Step 2: Convert to fraction form
    839.85/1,259.90 = 254.78/x
  3. Step 3: Cross multiply
    839.85x = 1,259.90 × 254.78
  4. Step 4: Simplify right side
    839.85x = 320,996.86
  5. Step 5: Solve for x
    x = 320,996.86/839.85
  6. Step 6: Final answer
    x = 382.21

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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.