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Finding the Fourth Proportional to 721.84, 1,082.22 and 640.84

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Solution

The fourth proportional to 721.84, 1,082.22 and 640.84 is: 960.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.84 : 1,082.22 = 640.84 : x
  2. Step 2: Convert to fraction form
    721.84/1,082.22 = 640.84/x
  3. Step 3: Cross multiply
    721.84x = 1,082.22 × 640.84
  4. Step 4: Simplify right side
    721.84x = 693,529.86
  5. Step 5: Solve for x
    x = 693,529.86/721.84
  6. Step 6: Final answer
    x = 960.78

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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.