Finding the Fourth Proportional to 100,146.32, 138,199.56 and 57,728.72

Step by Step Solution

1. Step 1: Write the proportion equation
   100,146.32 : 138,199.56 = 57,728.72 : x
2. Step 2: Convert to fraction form
   100,146.32/138,199.56 = 57,728.72/x
3. Step 3: Cross multiply
   100,146.32x = 138,199.56 × 57,728.72
4. Step 4: Simplify right side
   100,146.32x = 7,978,083,703.36
5. Step 5: Solve for x
   x = 7,978,083,703.36/100,146.32
6. Step 6: Final answer
   x = 79,664.27