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Finding the Fourth Proportional to 839.25, 1,258.67 and 319.31

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Solution

The fourth proportional to 839.25, 1,258.67 and 319.31 is: 478.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.25 : 1,258.67 = 319.31 : x
  2. Step 2: Convert to fraction form
    839.25/1,258.67 = 319.31/x
  3. Step 3: Cross multiply
    839.25x = 1,258.67 × 319.31
  4. Step 4: Simplify right side
    839.25x = 401,905.92
  5. Step 5: Solve for x
    x = 401,905.92/839.25
  6. Step 6: Final answer
    x = 478.89

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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.