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Finding the Fourth Proportional to 806.85, 1,211.30 and 685.88

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Solution

The fourth proportional to 806.85, 1,211.30 and 685.88 is: 1,029.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.85 : 1,211.30 = 685.88 : x
  2. Step 2: Convert to fraction form
    806.85/1,211.30 = 685.88/x
  3. Step 3: Cross multiply
    806.85x = 1,211.30 × 685.88
  4. Step 4: Simplify right side
    806.85x = 830,806.44
  5. Step 5: Solve for x
    x = 830,806.44/806.85
  6. Step 6: Final answer
    x = 1,029.69

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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.