Finding the Fourth Proportional to 100,019.43, 138,039.86 and 57,579.75

Step by Step Solution

1. Step 1: Write the proportion equation
   100,019.43 : 138,039.86 = 57,579.75 : x
2. Step 2: Convert to fraction form
   100,019.43/138,039.86 = 57,579.75/x
3. Step 3: Cross multiply
   100,019.43x = 138,039.86 × 57,579.75
4. Step 4: Simplify right side
   100,019.43x = 7,948,300,082.59
5. Step 5: Solve for x
   x = 7,948,300,082.59/100,019.43
6. Step 6: Final answer
   x = 79,467.56