Finding the Fourth Proportional to 11,958.78, 17,931.42 and 5,720.30

Step by Step Solution

1. Step 1: Write the proportion equation
   11,958.78 : 17,931.42 = 5,720.30 : x
2. Step 2: Convert to fraction form
   11,958.78/17,931.42 = 5,720.30/x
3. Step 3: Cross multiply
   11,958.78x = 17,931.42 × 5,720.30
4. Step 4: Simplify right side
   11,958.78x = 102,573,012.17
5. Step 5: Solve for x
   x = 102,573,012.17/11,958.78
6. Step 6: Final answer
   x = 8,577.21