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Finding the Fourth Proportional to 1,138.66, 1,571.36 and 641.31

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Solution

The fourth proportional to 1,138.66, 1,571.36 and 641.31 is: 885.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.66 : 1,571.36 = 641.31 : x
  2. Step 2: Convert to fraction form
    1,138.66/1,571.36 = 641.31/x
  3. Step 3: Cross multiply
    1,138.66x = 1,571.36 × 641.31
  4. Step 4: Simplify right side
    1,138.66x = 1,007,732.23
  5. Step 5: Solve for x
    x = 1,007,732.23/1,138.66
  6. Step 6: Final answer
    x = 885.01

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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.