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Finding the Third Proportional to 387 and 490

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Solution

The third proportional to 387 and 490 is: 620.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    387 : 490 = 490 : x
  2. Step 2: Convert to fraction form
    387/490 = 490/x
  3. Step 3: Cross multiply
    387x = 490 × 490
  4. Step 4: Simplify right side
    387x = 240,100
  5. Step 5: Solve for x
    x = 240,100/387
  6. Step 6: Final answer
    x = 620.41

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These problems maintain the same ratio (1.27) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.