Finding the Fourth Proportional to 128,632, 177,512.16 and 72,061.60

Step by Step Solution

1. Step 1: Write the proportion equation
   128,632 : 177,512.16 = 72,061.60 : x
2. Step 2: Convert to fraction form
   128,632/177,512.16 = 72,061.60/x
3. Step 3: Cross multiply
   128,632x = 177,512.16 × 72,061.60
4. Step 4: Simplify right side
   128,632x = 12,791,810,269.06
5. Step 5: Solve for x
   x = 12,791,810,269.06/128,632
6. Step 6: Final answer
   x = 99,445.01