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Finding the Third Proportional to 189 and 390

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Solution

The third proportional to 189 and 390 is: 804.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    189 : 390 = 390 : x
  2. Step 2: Convert to fraction form
    189/390 = 390/x
  3. Step 3: Cross multiply
    189x = 390 × 390
  4. Step 4: Simplify right side
    189x = 152,100
  5. Step 5: Solve for x
    x = 152,100/189
  6. Step 6: Final answer
    x = 804.76

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Why These Related Problems?

These problems maintain the same ratio (2.06) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.