Finding the Fourth Proportional to 87,109.55, 130,761.53 and 81,399.05

Step by Step Solution

1. Step 1: Write the proportion equation
   87,109.55 : 130,761.53 = 81,399.05 : x
2. Step 2: Convert to fraction form
   87,109.55/130,761.53 = 81,399.05/x
3. Step 3: Cross multiply
   87,109.55x = 130,761.53 × 81,399.05
4. Step 4: Simplify right side
   87,109.55x = 10,643,863,911.55
5. Step 5: Solve for x
   x = 10,643,863,911.55/87,109.55
6. Step 6: Final answer
   x = 122,189.40