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Finding the Fourth Proportional to 1,138.82, 1,571.61 and 641.55

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Solution

The fourth proportional to 1,138.82, 1,571.61 and 641.55 is: 885.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.82 : 1,571.61 = 641.55 : x
  2. Step 2: Convert to fraction form
    1,138.82/1,571.61 = 641.55/x
  3. Step 3: Cross multiply
    1,138.82x = 1,571.61 × 641.55
  4. Step 4: Simplify right side
    1,138.82x = 1,008,266.40
  5. Step 5: Solve for x
    x = 1,008,266.40/1,138.82
  6. Step 6: Final answer
    x = 885.36

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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.