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Finding the Third Proportional to 18 and 31.81

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Solution

The third proportional to 18 and 31.81 is: 56.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    18 : 31.81 = 31.81 : x
  2. Step 2: Convert to fraction form
    18/31.81 = 31.81/x
  3. Step 3: Cross multiply
    18x = 31.81 × 31.81
  4. Step 4: Simplify right side
    18x = 1,012.04
  5. Step 5: Solve for x
    x = 1,012.04/18
  6. Step 6: Final answer
    x = 56.22

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Why These Related Problems?

These problems maintain the same ratio (1.77) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.