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Finding the Third Proportional to 289.92 and 640.59

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Solution

The third proportional to 289.92 and 640.59 is: 1,415.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.92 : 640.59 = 640.59 : x
  2. Step 2: Convert to fraction form
    289.92/640.59 = 640.59/x
  3. Step 3: Cross multiply
    289.92x = 640.59 × 640.59
  4. Step 4: Simplify right side
    289.92x = 410,360.35
  5. Step 5: Solve for x
    x = 410,360.35/289.92
  6. Step 6: Final answer
    x = 1,415.42

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Why These Related Problems?

These problems maintain the same ratio (2.21) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.