Finding the Fourth Proportional to 20,659.55, 28,514.63 and 13,116.21

Step by Step Solution

1. Step 1: Write the proportion equation
   20,659.55 : 28,514.63 = 13,116.21 : x
2. Step 2: Convert to fraction form
   20,659.55/28,514.63 = 13,116.21/x
3. Step 3: Cross multiply
   20,659.55x = 28,514.63 × 13,116.21
4. Step 4: Simplify right side
   20,659.55x = 374,003,809.57
5. Step 5: Solve for x
   x = 374,003,809.57/20,659.55
6. Step 6: Final answer
   x = 18,103.20