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Finding the Fourth Proportional to 721.28, 1,081.58 and 331.28

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Solution

The fourth proportional to 721.28, 1,081.58 and 331.28 is: 496.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.28 : 1,081.58 = 331.28 : x
  2. Step 2: Convert to fraction form
    721.28/1,081.58 = 331.28/x
  3. Step 3: Cross multiply
    721.28x = 1,081.58 × 331.28
  4. Step 4: Simplify right side
    721.28x = 358,305.82
  5. Step 5: Solve for x
    x = 358,305.82/721.28
  6. Step 6: Final answer
    x = 496.76

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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.