Finding the Third Proportional to 91,409.50 and 138,878.50

Step by Step Solution

1. Step 1: Write the proportion equation
   91,409.50 : 138,878.50 = 138,878.50 : x
2. Step 2: Convert to fraction form
   91,409.50/138,878.50 = 138,878.50/x
3. Step 3: Cross multiply
   91,409.50x = 138,878.50 × 138,878.50
4. Step 4: Simplify right side
   91,409.50x = 19,287,237,762.25
5. Step 5: Solve for x
   x = 19,287,237,762.25/91,409.50
6. Step 6: Final answer
   x = 210,998.18