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Finding the Third Proportional to 18.51 and 39.81

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Solution

The third proportional to 18.51 and 39.81 is: 85.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.51 : 39.81 = 39.81 : x
  2. Step 2: Convert to fraction form
    18.51/39.81 = 39.81/x
  3. Step 3: Cross multiply
    18.51x = 39.81 × 39.81
  4. Step 4: Simplify right side
    18.51x = 1,585.19
  5. Step 5: Solve for x
    x = 1,585.19/18.51
  6. Step 6: Final answer
    x = 85.64

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Why These Related Problems?

These problems maintain the same ratio (2.15) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.