Finding the Third Proportional to 89.25 and 138.75

Step by Step Solution

1. Step 1: Write the proportion equation
   89.25 : 138.75 = 138.75 : x
2. Step 2: Convert to fraction form
   89.25/138.75 = 138.75/x
3. Step 3: Cross multiply
   89.25x = 138.75 × 138.75
4. Step 4: Simplify right side
   89.25x = 19,251.56
5. Step 5: Solve for x
   x = 19,251.56/89.25
6. Step 6: Final answer
   x = 215.70