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Finding the Fourth Proportional to 839.93, 1,259.75 and 319.91

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Solution

The fourth proportional to 839.93, 1,259.75 and 319.91 is: 479.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.93 : 1,259.75 = 319.91 : x
  2. Step 2: Convert to fraction form
    839.93/1,259.75 = 319.91/x
  3. Step 3: Cross multiply
    839.93x = 1,259.75 × 319.91
  4. Step 4: Simplify right side
    839.93x = 402,998.72
  5. Step 5: Solve for x
    x = 402,998.72/839.93
  6. Step 6: Final answer
    x = 479.80

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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.