Finding the Fourth Proportional to 85,405.20, 128,185.54 and 45,457.72

Step by Step Solution

1. Step 1: Write the proportion equation
   85,405.20 : 128,185.54 = 45,457.72 : x
2. Step 2: Convert to fraction form
   85,405.20/128,185.54 = 45,457.72/x
3. Step 3: Cross multiply
   85,405.20x = 128,185.54 × 45,457.72
4. Step 4: Simplify right side
   85,405.20x = 5,827,022,385.37
5. Step 5: Solve for x
   x = 5,827,022,385.37/85,405.20
6. Step 6: Final answer
   x = 68,227.96