Finding the Fourth Proportional to 13,121, 18,106.76 and 7,152.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,121 : 18,106.76 = 7,152.72 : x
2. Step 2: Convert to fraction form
   13,121/18,106.76 = 7,152.72/x
3. Step 3: Cross multiply
   13,121x = 18,106.76 × 7,152.72
4. Step 4: Simplify right side
   13,121x = 129,512,584.39
5. Step 5: Solve for x
   x = 129,512,584.39/13,121
6. Step 6: Final answer
   x = 9,870.63