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Finding the Fourth Proportional to 1,638.43, 2,458.55 and 665.21

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Solution

The fourth proportional to 1,638.43, 2,458.55 and 665.21 is: 998.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,638.43 : 2,458.55 = 665.21 : x
  2. Step 2: Convert to fraction form
    1,638.43/2,458.55 = 665.21/x
  3. Step 3: Cross multiply
    1,638.43x = 2,458.55 × 665.21
  4. Step 4: Simplify right side
    1,638.43x = 1,635,459.85
  5. Step 5: Solve for x
    x = 1,635,459.85/1,638.43
  6. Step 6: Final answer
    x = 998.19

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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.