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Finding the Fourth Proportional to 789.16, 1,089.66 and 641.56

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Solution

The fourth proportional to 789.16, 1,089.66 and 641.56 is: 885.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.16 : 1,089.66 = 641.56 : x
  2. Step 2: Convert to fraction form
    789.16/1,089.66 = 641.56/x
  3. Step 3: Cross multiply
    789.16x = 1,089.66 × 641.56
  4. Step 4: Simplify right side
    789.16x = 699,082.27
  5. Step 5: Solve for x
    x = 699,082.27/789.16
  6. Step 6: Final answer
    x = 885.86

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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.