Finding the Third Proportional to 66,909.80 and 90,826.31

Step by Step Solution

1. Step 1: Write the proportion equation
   66,909.80 : 90,826.31 = 90,826.31 : x
2. Step 2: Convert to fraction form
   66,909.80/90,826.31 = 90,826.31/x
3. Step 3: Cross multiply
   66,909.80x = 90,826.31 × 90,826.31
4. Step 4: Simplify right side
   66,909.80x = 8,249,419,042.35
5. Step 5: Solve for x
   x = 8,249,419,042.35/66,909.80
6. Step 6: Final answer
   x = 123,291.65