Finding the Fourth Proportional to 31,086.36, 42,899.76 and 18,518.40

Step by Step Solution

1. Step 1: Write the proportion equation
   31,086.36 : 42,899.76 = 18,518.40 : x
2. Step 2: Convert to fraction form
   31,086.36/42,899.76 = 18,518.40/x
3. Step 3: Cross multiply
   31,086.36x = 42,899.76 × 18,518.40
4. Step 4: Simplify right side
   31,086.36x = 794,434,915.58
5. Step 5: Solve for x
   x = 794,434,915.58/31,086.36
6. Step 6: Final answer
   x = 25,555.74