Finding the Fourth Proportional to 99,640, 137,503.20 and 54,928.96

Step by Step Solution

1. Step 1: Write the proportion equation
   99,640 : 137,503.20 = 54,928.96 : x
2. Step 2: Convert to fraction form
   99,640/137,503.20 = 54,928.96/x
3. Step 3: Cross multiply
   99,640x = 137,503.20 × 54,928.96
4. Step 4: Simplify right side
   99,640x = 7,552,907,772.67
5. Step 5: Solve for x
   x = 7,552,907,772.67/99,640
6. Step 6: Final answer
   x = 75,801.96