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Finding the Fourth Proportional to 911.13, 1,255.85 and 645.23

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Solution

The fourth proportional to 911.13, 1,255.85 and 645.23 is: 889.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.13 : 1,255.85 = 645.23 : x
  2. Step 2: Convert to fraction form
    911.13/1,255.85 = 645.23/x
  3. Step 3: Cross multiply
    911.13x = 1,255.85 × 645.23
  4. Step 4: Simplify right side
    911.13x = 810,314.43
  5. Step 5: Solve for x
    x = 810,314.43/911.13
  6. Step 6: Final answer
    x = 889.35

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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.