Finding the Fourth Proportional to 91,590.12, 138,091.50 and 91,021.50

Step by Step Solution

1. Step 1: Write the proportion equation
   91,590.12 : 138,091.50 = 91,021.50 : x
2. Step 2: Convert to fraction form
   91,590.12/138,091.50 = 91,021.50/x
3. Step 3: Cross multiply
   91,590.12x = 138,091.50 × 91,021.50
4. Step 4: Simplify right side
   91,590.12x = 12,569,295,467.25
5. Step 5: Solve for x
   x = 12,569,295,467.25/91,590.12
6. Step 6: Final answer
   x = 137,234.18