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Finding the Fourth Proportional to 1,138.68, 1,571.25 and 641.29

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Solution

The fourth proportional to 1,138.68, 1,571.25 and 641.29 is: 884.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.68 : 1,571.25 = 641.29 : x
  2. Step 2: Convert to fraction form
    1,138.68/1,571.25 = 641.29/x
  3. Step 3: Cross multiply
    1,138.68x = 1,571.25 × 641.29
  4. Step 4: Simplify right side
    1,138.68x = 1,007,626.91
  5. Step 5: Solve for x
    x = 1,007,626.91/1,138.68
  6. Step 6: Final answer
    x = 884.91

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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.