Finding the Fourth Proportional to 11,685.81, 17,518.29 and 4,288.55

Step by Step Solution

1. Step 1: Write the proportion equation
   11,685.81 : 17,518.29 = 4,288.55 : x
2. Step 2: Convert to fraction form
   11,685.81/17,518.29 = 4,288.55/x
3. Step 3: Cross multiply
   11,685.81x = 17,518.29 × 4,288.55
4. Step 4: Simplify right side
   11,685.81x = 75,128,081.57
5. Step 5: Solve for x
   x = 75,128,081.57/11,685.81
6. Step 6: Final answer
   x = 6,429.00