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Finding the Third Proportional to 389 and 660

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Solution

The third proportional to 389 and 660 is: 1,119.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    389 : 660 = 660 : x
  2. Step 2: Convert to fraction form
    389/660 = 660/x
  3. Step 3: Cross multiply
    389x = 660 × 660
  4. Step 4: Simplify right side
    389x = 435,600
  5. Step 5: Solve for x
    x = 435,600/389
  6. Step 6: Final answer
    x = 1,119.79

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Why These Related Problems?

These problems maintain the same ratio (1.70) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.