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Finding the Fourth Proportional to 1,138.62, 1,571.30 and 641.21

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Solution

The fourth proportional to 1,138.62, 1,571.30 and 641.21 is: 884.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.62 : 1,571.30 = 641.21 : x
  2. Step 2: Convert to fraction form
    1,138.62/1,571.30 = 641.21/x
  3. Step 3: Cross multiply
    1,138.62x = 1,571.30 × 641.21
  4. Step 4: Simplify right side
    1,138.62x = 1,007,540.01
  5. Step 5: Solve for x
    x = 1,007,540.01/1,138.62
  6. Step 6: Final answer
    x = 884.88

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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.