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Finding the Fourth Proportional to 789.75, 1,089.05 and 641.93

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Solution

The fourth proportional to 789.75, 1,089.05 and 641.93 is: 885.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.75 : 1,089.05 = 641.93 : x
  2. Step 2: Convert to fraction form
    789.75/1,089.05 = 641.93/x
  3. Step 3: Cross multiply
    789.75x = 1,089.05 × 641.93
  4. Step 4: Simplify right side
    789.75x = 699,085.21
  5. Step 5: Solve for x
    x = 699,085.21/789.75
  6. Step 6: Final answer
    x = 885.20

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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.