Finding the Fourth Proportional to 9,912.89, 13,680.19 and 5,436.80

Step by Step Solution

1. Step 1: Write the proportion equation
   9,912.89 : 13,680.19 = 5,436.80 : x
2. Step 2: Convert to fraction form
   9,912.89/13,680.19 = 5,436.80/x
3. Step 3: Cross multiply
   9,912.89x = 13,680.19 × 5,436.80
4. Step 4: Simplify right side
   9,912.89x = 74,376,493.06
5. Step 5: Solve for x
   x = 74,376,493.06/9,912.89
6. Step 6: Final answer
   x = 7,503.01