Finding the Fourth Proportional to 15,499.58, 21,389.63 and 8,426.15

Step by Step Solution

1. Step 1: Write the proportion equation
   15,499.58 : 21,389.63 = 8,426.15 : x
2. Step 2: Convert to fraction form
   15,499.58/21,389.63 = 8,426.15/x
3. Step 3: Cross multiply
   15,499.58x = 21,389.63 × 8,426.15
4. Step 4: Simplify right side
   15,499.58x = 180,232,081.75
5. Step 5: Solve for x
   x = 180,232,081.75/15,499.58
6. Step 6: Final answer
   x = 11,628.20