Finding the Fourth Proportional to 128,623, 177,499.80 and 72,034.39

Step by Step Solution

1. Step 1: Write the proportion equation
   128,623 : 177,499.80 = 72,034.39 : x
2. Step 2: Convert to fraction form
   128,623/177,499.80 = 72,034.39/x
3. Step 3: Cross multiply
   128,623x = 177,499.80 × 72,034.39
4. Step 4: Simplify right side
   128,623x = 12,786,089,818.12
5. Step 5: Solve for x
   x = 12,786,089,818.12/128,623
6. Step 6: Final answer
   x = 99,407.49