Finding the Third Proportional to 89.81 and 138.13

Step by Step Solution

1. Step 1: Write the proportion equation
   89.81 : 138.13 = 138.13 : x
2. Step 2: Convert to fraction form
   89.81/138.13 = 138.13/x
3. Step 3: Cross multiply
   89.81x = 138.13 × 138.13
4. Step 4: Simplify right side
   89.81x = 19,078.52
5. Step 5: Solve for x
   x = 19,078.52/89.81
6. Step 6: Final answer
   x = 212.43