Finding the Fourth Proportional to 81,145.68, 121,618.04 and 45,978.72

Step by Step Solution

1. Step 1: Write the proportion equation
   81,145.68 : 121,618.04 = 45,978.72 : x
2. Step 2: Convert to fraction form
   81,145.68/121,618.04 = 45,978.72/x
3. Step 3: Cross multiply
   81,145.68x = 121,618.04 × 45,978.72
4. Step 4: Simplify right side
   81,145.68x = 5,591,841,808.11
5. Step 5: Solve for x
   x = 5,591,841,808.11/81,145.68
6. Step 6: Final answer
   x = 68,911.15