Finding the Fourth Proportional to 13,478.40, 18,597.12 and 7,886.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,478.40 : 18,597.12 = 7,886.72 : x
2. Step 2: Convert to fraction form
   13,478.40/18,597.12 = 7,886.72/x
3. Step 3: Cross multiply
   13,478.40x = 18,597.12 × 7,886.72
4. Step 4: Simplify right side
   13,478.40x = 146,670,278.25
5. Step 5: Solve for x
   x = 146,670,278.25/13,478.40
6. Step 6: Final answer
   x = 10,881.88