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Finding the Fourth Proportional to 2,105, 3,157.44 and 643.94

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Solution

The fourth proportional to 2,105, 3,157.44 and 643.94 is: 965.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,105 : 3,157.44 = 643.94 : x
  2. Step 2: Convert to fraction form
    2,105/3,157.44 = 643.94/x
  3. Step 3: Cross multiply
    2,105x = 3,157.44 × 643.94
  4. Step 4: Simplify right side
    2,105x = 2,033,201.91
  5. Step 5: Solve for x
    x = 2,033,201.91/2,105
  6. Step 6: Final answer
    x = 965.89

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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.