Finding the Fourth Proportional to 128,783.78, 177,722.04 and 72,191.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,783.78 : 177,722.04 = 72,191.50 : x
2. Step 2: Convert to fraction form
   128,783.78/177,722.04 = 72,191.50/x
3. Step 3: Cross multiply
   128,783.78x = 177,722.04 × 72,191.50
4. Step 4: Simplify right side
   128,783.78x = 12,830,020,650.66
5. Step 5: Solve for x
   x = 12,830,020,650.66/128,783.78
6. Step 6: Final answer
   x = 99,624.51