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Finding the Fourth Proportional to 778.09, 1,166.90 and 640.79

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Solution

The fourth proportional to 778.09, 1,166.90 and 640.79 is: 960.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.09 : 1,166.90 = 640.79 : x
  2. Step 2: Convert to fraction form
    778.09/1,166.90 = 640.79/x
  3. Step 3: Cross multiply
    778.09x = 1,166.90 × 640.79
  4. Step 4: Simplify right side
    778.09x = 747,734.65
  5. Step 5: Solve for x
    x = 747,734.65/778.09
  6. Step 6: Final answer
    x = 960.99

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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.