Finding the Fourth Proportional to 156,314.72, 215,704.08 and 99,720

Step by Step Solution

1. Step 1: Write the proportion equation
   156,314.72 : 215,704.08 = 99,720 : x
2. Step 2: Convert to fraction form
   156,314.72/215,704.08 = 99,720/x
3. Step 3: Cross multiply
   156,314.72x = 215,704.08 × 99,720
4. Step 4: Simplify right side
   156,314.72x = 21,510,010,857.60
5. Step 5: Solve for x
   x = 21,510,010,857.60/156,314.72
6. Step 6: Final answer
   x = 137,607.07