Finding the Fourth Proportional to 21,856.72, 30,152.64 and 13,478.08

Step by Step Solution

1. Step 1: Write the proportion equation
   21,856.72 : 30,152.64 = 13,478.08 : x
2. Step 2: Convert to fraction form
   21,856.72/30,152.64 = 13,478.08/x
3. Step 3: Cross multiply
   21,856.72x = 30,152.64 × 13,478.08
4. Step 4: Simplify right side
   21,856.72x = 406,399,694.13
5. Step 5: Solve for x
   x = 406,399,694.13/21,856.72
6. Step 6: Final answer
   x = 18,593.81