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Finding the Fourth Proportional to 722.79, 1,084.21 and 311.85

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Solution

The fourth proportional to 722.79, 1,084.21 and 311.85 is: 467.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    722.79 : 1,084.21 = 311.85 : x
  2. Step 2: Convert to fraction form
    722.79/1,084.21 = 311.85/x
  3. Step 3: Cross multiply
    722.79x = 1,084.21 × 311.85
  4. Step 4: Simplify right side
    722.79x = 338,110.11
  5. Step 5: Solve for x
    x = 338,110.11/722.79
  6. Step 6: Final answer
    x = 467.78

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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.