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Finding the Third Proportional to 1,089 and 1,221

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Solution

The third proportional to 1,089 and 1,221 is: 1,369

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,089 : 1,221 = 1,221 : x
  2. Step 2: Convert to fraction form
    1,089/1,221 = 1,221/x
  3. Step 3: Cross multiply
    1,089x = 1,221 × 1,221
  4. Step 4: Simplify right side
    1,089x = 1,490,841
  5. Step 5: Solve for x
    x = 1,490,841/1,089
  6. Step 6: Final answer
    x = 1,369

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Why These Related Problems?

These problems maintain the same ratio (1.12) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.