Finding the Fourth Proportional to 13,501.60, 18,640.88 and 8,472.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,501.60 : 18,640.88 = 8,472.72 : x
2. Step 2: Convert to fraction form
   13,501.60/18,640.88 = 8,472.72/x
3. Step 3: Cross multiply
   13,501.60x = 18,640.88 × 8,472.72
4. Step 4: Simplify right side
   13,501.60x = 157,938,956.79
5. Step 5: Solve for x
   x = 157,938,956.79/13,501.60
6. Step 6: Final answer
   x = 11,697.80