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Finding the Fourth Proportional to 721.31, 1,081.42 and 648

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Solution

The fourth proportional to 721.31, 1,081.42 and 648 is: 971.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.31 : 1,081.42 = 648 : x
  2. Step 2: Convert to fraction form
    721.31/1,081.42 = 648/x
  3. Step 3: Cross multiply
    721.31x = 1,081.42 × 648
  4. Step 4: Simplify right side
    721.31x = 700,758.54
  5. Step 5: Solve for x
    x = 700,758.54/721.31
  6. Step 6: Final answer
    x = 971.51

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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.