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Finding the Third Proportional to 387 and 396

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Solution

The third proportional to 387 and 396 is: 405.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    387 : 396 = 396 : x
  2. Step 2: Convert to fraction form
    387/396 = 396/x
  3. Step 3: Cross multiply
    387x = 396 × 396
  4. Step 4: Simplify right side
    387x = 156,816
  5. Step 5: Solve for x
    x = 156,816/387
  6. Step 6: Final answer
    x = 405.21

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These problems maintain the same ratio (1.02) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.