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Finding the Fourth Proportional to 839.98, 1,259.97 and 319.86

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Solution

The fourth proportional to 839.98, 1,259.97 and 319.86 is: 479.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.98 : 1,259.97 = 319.86 : x
  2. Step 2: Convert to fraction form
    839.98/1,259.97 = 319.86/x
  3. Step 3: Cross multiply
    839.98x = 1,259.97 × 319.86
  4. Step 4: Simplify right side
    839.98x = 403,008.08
  5. Step 5: Solve for x
    x = 403,008.08/839.98
  6. Step 6: Final answer
    x = 479.78

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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.