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Finding the Fourth Proportional to 839.35, 1,257.34 and 393.98

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Solution

The fourth proportional to 839.35, 1,257.34 and 393.98 is: 590.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.35 : 1,257.34 = 393.98 : x
  2. Step 2: Convert to fraction form
    839.35/1,257.34 = 393.98/x
  3. Step 3: Cross multiply
    839.35x = 1,257.34 × 393.98
  4. Step 4: Simplify right side
    839.35x = 495,366.81
  5. Step 5: Solve for x
    x = 495,366.81/839.35
  6. Step 6: Final answer
    x = 590.18

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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.