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Finding the Fourth Proportional to 807.85, 1,211.86 and 259.90

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Solution

The fourth proportional to 807.85, 1,211.86 and 259.90 is: 389.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.85 : 1,211.86 = 259.90 : x
  2. Step 2: Convert to fraction form
    807.85/1,211.86 = 259.90/x
  3. Step 3: Cross multiply
    807.85x = 1,211.86 × 259.90
  4. Step 4: Simplify right side
    807.85x = 314,958.73
  5. Step 5: Solve for x
    x = 314,958.73/807.85
  6. Step 6: Final answer
    x = 389.87

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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.