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Finding the Fourth Proportional to 728.09, 1,091.48 and 381.21

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Solution

The fourth proportional to 728.09, 1,091.48 and 381.21 is: 571.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.09 : 1,091.48 = 381.21 : x
  2. Step 2: Convert to fraction form
    728.09/1,091.48 = 381.21/x
  3. Step 3: Cross multiply
    728.09x = 1,091.48 × 381.21
  4. Step 4: Simplify right side
    728.09x = 416,077.09
  5. Step 5: Solve for x
    x = 416,077.09/728.09
  6. Step 6: Final answer
    x = 571.46

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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.