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Finding the Fourth Proportional to 839.70, 1,257.63 and 821.46

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Solution

The fourth proportional to 839.70, 1,257.63 and 821.46 is: 1,230.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.70 : 1,257.63 = 821.46 : x
  2. Step 2: Convert to fraction form
    839.70/1,257.63 = 821.46/x
  3. Step 3: Cross multiply
    839.70x = 1,257.63 × 821.46
  4. Step 4: Simplify right side
    839.70x = 1,033,092.74
  5. Step 5: Solve for x
    x = 1,033,092.74/839.70
  6. Step 6: Final answer
    x = 1,230.31

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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.