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Finding the Fourth Proportional to 861.42, 1,285.49 and 769.13

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Solution

The fourth proportional to 861.42, 1,285.49 and 769.13 is: 1,147.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.42 : 1,285.49 = 769.13 : x
  2. Step 2: Convert to fraction form
    861.42/1,285.49 = 769.13/x
  3. Step 3: Cross multiply
    861.42x = 1,285.49 × 769.13
  4. Step 4: Simplify right side
    861.42x = 988,698.65
  5. Step 5: Solve for x
    x = 988,698.65/861.42
  6. Step 6: Final answer
    x = 1,147.75

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.