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Finding the Third Proportional to 290.75 and 639.38

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Solution

The third proportional to 290.75 and 639.38 is: 1,406.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.75 : 639.38 = 639.38 : x
  2. Step 2: Convert to fraction form
    290.75/639.38 = 639.38/x
  3. Step 3: Cross multiply
    290.75x = 639.38 × 639.38
  4. Step 4: Simplify right side
    290.75x = 408,800.39
  5. Step 5: Solve for x
    x = 408,800.39/290.75
  6. Step 6: Final answer
    x = 1,406.02

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Why These Related Problems?

These problems maintain the same ratio (2.20) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.