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Finding the Fourth Proportional to 839.26, 1,258.78 and 319.12

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Solution

The fourth proportional to 839.26, 1,258.78 and 319.12 is: 478.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.26 : 1,258.78 = 319.12 : x
  2. Step 2: Convert to fraction form
    839.26/1,258.78 = 319.12/x
  3. Step 3: Cross multiply
    839.26x = 1,258.78 × 319.12
  4. Step 4: Simplify right side
    839.26x = 401,701.87
  5. Step 5: Solve for x
    x = 401,701.87/839.26
  6. Step 6: Final answer
    x = 478.64

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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.