Finding the Fourth Proportional to 128,741.72, 177,653.80 and 72,142.16

Step by Step Solution

1. Step 1: Write the proportion equation
   128,741.72 : 177,653.80 = 72,142.16 : x
2. Step 2: Convert to fraction form
   128,741.72/177,653.80 = 72,142.16/x
3. Step 3: Cross multiply
   128,741.72x = 177,653.80 × 72,142.16
4. Step 4: Simplify right side
   128,741.72x = 12,816,328,864.21
5. Step 5: Solve for x
   x = 12,816,328,864.21/128,741.72
6. Step 6: Final answer
   x = 99,550.70