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Finding the Fourth Proportional to 721.40, 1,076.86 and 668

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Solution

The fourth proportional to 721.40, 1,076.86 and 668 is: 997.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.40 : 1,076.86 = 668 : x
  2. Step 2: Convert to fraction form
    721.40/1,076.86 = 668/x
  3. Step 3: Cross multiply
    721.40x = 1,076.86 × 668
  4. Step 4: Simplify right side
    721.40x = 719,342.48
  5. Step 5: Solve for x
    x = 719,342.48/721.40
  6. Step 6: Final answer
    x = 997.15

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.