Finding the Fourth Proportional to 3,485.60, 5,221.12 and 2,618.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,485.60 : 5,221.12 = 2,618.72 : x
2. Step 2: Convert to fraction form
   3,485.60/5,221.12 = 2,618.72/x
3. Step 3: Cross multiply
   3,485.60x = 5,221.12 × 2,618.72
4. Step 4: Simplify right side
   3,485.60x = 13,672,651.37
5. Step 5: Solve for x
   x = 13,672,651.37/3,485.60
6. Step 6: Final answer
   x = 3,922.61