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Finding the Fourth Proportional to 721.72, 1,082.78 and 311.12

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Solution

The fourth proportional to 721.72, 1,082.78 and 311.12 is: 466.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.72 : 1,082.78 = 311.12 : x
  2. Step 2: Convert to fraction form
    721.72/1,082.78 = 311.12/x
  3. Step 3: Cross multiply
    721.72x = 1,082.78 × 311.12
  4. Step 4: Simplify right side
    721.72x = 336,874.51
  5. Step 5: Solve for x
    x = 336,874.51/721.72
  6. Step 6: Final answer
    x = 466.77

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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.