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Finding the Fourth Proportional to 807.67, 1,211.72 and 287.80

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Solution

The fourth proportional to 807.67, 1,211.72 and 287.80 is: 431.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.67 : 1,211.72 = 287.80 : x
  2. Step 2: Convert to fraction form
    807.67/1,211.72 = 287.80/x
  3. Step 3: Cross multiply
    807.67x = 1,211.72 × 287.80
  4. Step 4: Simplify right side
    807.67x = 348,733.02
  5. Step 5: Solve for x
    x = 348,733.02/807.67
  6. Step 6: Final answer
    x = 431.78

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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.