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Finding the Fourth Proportional to 784.36, 1,081.75 and 489.31

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Solution

The fourth proportional to 784.36, 1,081.75 and 489.31 is: 674.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.36 : 1,081.75 = 489.31 : x
  2. Step 2: Convert to fraction form
    784.36/1,081.75 = 489.31/x
  3. Step 3: Cross multiply
    784.36x = 1,081.75 × 489.31
  4. Step 4: Simplify right side
    784.36x = 529,311.09
  5. Step 5: Solve for x
    x = 529,311.09/784.36
  6. Step 6: Final answer
    x = 674.83

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.