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Finding the Fourth Proportional to 2,659.40, 3,989.22 and 810.78

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Solution

The fourth proportional to 2,659.40, 3,989.22 and 810.78 is: 1,216.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,659.40 : 3,989.22 = 810.78 : x
  2. Step 2: Convert to fraction form
    2,659.40/3,989.22 = 810.78/x
  3. Step 3: Cross multiply
    2,659.40x = 3,989.22 × 810.78
  4. Step 4: Simplify right side
    2,659.40x = 3,234,379.79
  5. Step 5: Solve for x
    x = 3,234,379.79/2,659.40
  6. Step 6: Final answer
    x = 1,216.21

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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.