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Finding the Fourth Proportional to 721.11, 1,080.96 and 391.75

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Solution

The fourth proportional to 721.11, 1,080.96 and 391.75 is: 587.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.11 : 1,080.96 = 391.75 : x
  2. Step 2: Convert to fraction form
    721.11/1,080.96 = 391.75/x
  3. Step 3: Cross multiply
    721.11x = 1,080.96 × 391.75
  4. Step 4: Simplify right side
    721.11x = 423,466.08
  5. Step 5: Solve for x
    x = 423,466.08/721.11
  6. Step 6: Final answer
    x = 587.24

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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.