Finding the Fourth Proportional to 13,106.85, 18,087.30 and 7,138.50

Step by Step Solution

1. Step 1: Write the proportion equation
   13,106.85 : 18,087.30 = 7,138.50 : x
2. Step 2: Convert to fraction form
   13,106.85/18,087.30 = 7,138.50/x
3. Step 3: Cross multiply
   13,106.85x = 18,087.30 × 7,138.50
4. Step 4: Simplify right side
   13,106.85x = 129,116,123.22
5. Step 5: Solve for x
   x = 129,116,123.22/13,106.85
6. Step 6: Final answer
   x = 9,851.04