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Finding the Fourth Proportional to 721.70, 1,082.56 and 259.81

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Solution

The fourth proportional to 721.70, 1,082.56 and 259.81 is: 389.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.70 : 1,082.56 = 259.81 : x
  2. Step 2: Convert to fraction form
    721.70/1,082.56 = 259.81/x
  3. Step 3: Cross multiply
    721.70x = 1,082.56 × 259.81
  4. Step 4: Simplify right side
    721.70x = 281,257.91
  5. Step 5: Solve for x
    x = 281,257.91/721.70
  6. Step 6: Final answer
    x = 389.72

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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.