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Finding the Fourth Proportional to 1,280.43, 1,766.70 and 861.57

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Solution

The fourth proportional to 1,280.43, 1,766.70 and 861.57 is: 1,188.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.43 : 1,766.70 = 861.57 : x
  2. Step 2: Convert to fraction form
    1,280.43/1,766.70 = 861.57/x
  3. Step 3: Cross multiply
    1,280.43x = 1,766.70 × 861.57
  4. Step 4: Simplify right side
    1,280.43x = 1,522,135.72
  5. Step 5: Solve for x
    x = 1,522,135.72/1,280.43
  6. Step 6: Final answer
    x = 1,188.77

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.