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Finding the Third Proportional to 640.25 and 915.38

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Solution

The third proportional to 640.25 and 915.38 is: 1,308.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.25 : 915.38 = 915.38 : x
  2. Step 2: Convert to fraction form
    640.25/915.38 = 915.38/x
  3. Step 3: Cross multiply
    640.25x = 915.38 × 915.38
  4. Step 4: Simplify right side
    640.25x = 837,911.39
  5. Step 5: Solve for x
    x = 837,911.39/640.25
  6. Step 6: Final answer
    x = 1,308.73

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Why These Related Problems?

These problems maintain the same ratio (1.43) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.