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Finding the Fourth Proportional to 872.67, 1,309.20 and 287.86

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Solution

The fourth proportional to 872.67, 1,309.20 and 287.86 is: 431.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.67 : 1,309.20 = 287.86 : x
  2. Step 2: Convert to fraction form
    872.67/1,309.20 = 287.86/x
  3. Step 3: Cross multiply
    872.67x = 1,309.20 × 287.86
  4. Step 4: Simplify right side
    872.67x = 376,860.49
  5. Step 5: Solve for x
    x = 376,860.49/872.67
  6. Step 6: Final answer
    x = 431.85

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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.