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Finding the Third Proportional to 1,288 and 1,690

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Solution

The third proportional to 1,288 and 1,690 is: 2,217.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288 : 1,690 = 1,690 : x
  2. Step 2: Convert to fraction form
    1,288/1,690 = 1,690/x
  3. Step 3: Cross multiply
    1,288x = 1,690 × 1,690
  4. Step 4: Simplify right side
    1,288x = 2,856,100
  5. Step 5: Solve for x
    x = 2,856,100/1,288
  6. Step 6: Final answer
    x = 2,217.47

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Why These Related Problems?

These problems maintain the same ratio (1.31) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.