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Finding the Fourth Proportional to 721.43, 1,082.12 and 208.43

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Solution

The fourth proportional to 721.43, 1,082.12 and 208.43 is: 312.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.43 : 1,082.12 = 208.43 : x
  2. Step 2: Convert to fraction form
    721.43/1,082.12 = 208.43/x
  3. Step 3: Cross multiply
    721.43x = 1,082.12 × 208.43
  4. Step 4: Simplify right side
    721.43x = 225,546.27
  5. Step 5: Solve for x
    x = 225,546.27/721.43
  6. Step 6: Final answer
    x = 312.64

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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.