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Finding the Fourth Proportional to 855.85, 1,283.79 and 640.93

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Solution

The fourth proportional to 855.85, 1,283.79 and 640.93 is: 961.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.85 : 1,283.79 = 640.93 : x
  2. Step 2: Convert to fraction form
    855.85/1,283.79 = 640.93/x
  3. Step 3: Cross multiply
    855.85x = 1,283.79 × 640.93
  4. Step 4: Simplify right side
    855.85x = 822,819.52
  5. Step 5: Solve for x
    x = 822,819.52/855.85
  6. Step 6: Final answer
    x = 961.41

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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.