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Finding the Third Proportional to 420,378 and 640,287

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Solution

The third proportional to 420,378 and 640,287 is: 975,235.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    420,378 : 640,287 = 640,287 : x
  2. Step 2: Convert to fraction form
    420,378/640,287 = 640,287/x
  3. Step 3: Cross multiply
    420,378x = 640,287 × 640,287
  4. Step 4: Simplify right side
    420,378x = 409,967,442,369
  5. Step 5: Solve for x
    x = 409,967,442,369/420,378
  6. Step 6: Final answer
    x = 975,235.25

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Why These Related Problems?

These problems maintain the same ratio (1.52) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.