Finding the Fourth Proportional to 128,861.48, 177,837.72 and 72,276.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,861.48 : 177,837.72 = 72,276.50 : x
2. Step 2: Convert to fraction form
   128,861.48/177,837.72 = 72,276.50/x
3. Step 3: Cross multiply
   128,861.48x = 177,837.72 × 72,276.50
4. Step 4: Simplify right side
   128,861.48x = 12,853,487,969.58
5. Step 5: Solve for x
   x = 12,853,487,969.58/128,861.48
6. Step 6: Final answer
   x = 99,746.55