Finding the Fourth Proportional to 150,855.57, 208,215 and 99,870.21

Step by Step Solution

1. Step 1: Write the proportion equation
   150,855.57 : 208,215 = 99,870.21 : x
2. Step 2: Convert to fraction form
   150,855.57/208,215 = 99,870.21/x
3. Step 3: Cross multiply
   150,855.57x = 208,215 × 99,870.21
4. Step 4: Simplify right side
   150,855.57x = 20,794,475,775.15
5. Step 5: Solve for x
   x = 20,794,475,775.15/150,855.57
6. Step 6: Final answer
   x = 137,843.61