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Finding the Third Proportional to 90 and 121

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Solution

The third proportional to 90 and 121 is: 162.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    90 : 121 = 121 : x
  2. Step 2: Convert to fraction form
    90/121 = 121/x
  3. Step 3: Cross multiply
    90x = 121 × 121
  4. Step 4: Simplify right side
    90x = 14,641
  5. Step 5: Solve for x
    x = 14,641/90
  6. Step 6: Final answer
    x = 162.68

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Why These Related Problems?

These problems maintain the same ratio (1.34) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.