Finding the Fourth Proportional to 13,085.60, 18,055.68 and 7,781.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,085.60 : 18,055.68 = 7,781.72 : x
2. Step 2: Convert to fraction form
   13,085.60/18,055.68 = 7,781.72/x
3. Step 3: Cross multiply
   13,085.60x = 18,055.68 × 7,781.72
4. Step 4: Simplify right side
   13,085.60x = 140,504,246.17
5. Step 5: Solve for x
   x = 140,504,246.17/13,085.60
6. Step 6: Final answer
   x = 10,737.32