Finding the Fourth Proportional to 99,839.20, 137,783.72 and 54,521.40

Step by Step Solution

1. Step 1: Write the proportion equation
   99,839.20 : 137,783.72 = 54,521.40 : x
2. Step 2: Convert to fraction form
   99,839.20/137,783.72 = 54,521.40/x
3. Step 3: Cross multiply
   99,839.20x = 137,783.72 × 54,521.40
4. Step 4: Simplify right side
   99,839.20x = 7,512,161,311.61
5. Step 5: Solve for x
   x = 7,512,161,311.61/99,839.20
6. Step 6: Final answer
   x = 75,242.60