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Finding the Fourth Proportional to 911.45, 1,255.45 and 645.43

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Solution

The fourth proportional to 911.45, 1,255.45 and 645.43 is: 889.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.45 : 1,255.45 = 645.43 : x
  2. Step 2: Convert to fraction form
    911.45/1,255.45 = 645.43/x
  3. Step 3: Cross multiply
    911.45x = 1,255.45 × 645.43
  4. Step 4: Simplify right side
    911.45x = 810,305.09
  5. Step 5: Solve for x
    x = 810,305.09/911.45
  6. Step 6: Final answer
    x = 889.03

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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.