Finding the Fourth Proportional to 31,068.79, 42,876 and 17,639.60

Step by Step Solution

1. Step 1: Write the proportion equation
   31,068.79 : 42,876 = 17,639.60 : x
2. Step 2: Convert to fraction form
   31,068.79/42,876 = 17,639.60/x
3. Step 3: Cross multiply
   31,068.79x = 42,876 × 17,639.60
4. Step 4: Simplify right side
   31,068.79x = 756,315,275.22
5. Step 5: Solve for x
   x = 756,315,275.22/31,068.79
6. Step 6: Final answer
   x = 24,343.25