Finding the Fourth Proportional to 105,081.42, 145,012.84 and 57,335.78

Step by Step Solution

1. Step 1: Write the proportion equation
   105,081.42 : 145,012.84 = 57,335.78 : x
2. Step 2: Convert to fraction form
   105,081.42/145,012.84 = 57,335.78/x
3. Step 3: Cross multiply
   105,081.42x = 145,012.84 × 57,335.78
4. Step 4: Simplify right side
   105,081.42x = 8,314,424,291.42
5. Step 5: Solve for x
   x = 8,314,424,291.42/105,081.42
6. Step 6: Final answer
   x = 79,123.64