Finding the Fourth Proportional to 21,990.72, 30,348.18 and 15,624.12

Step by Step Solution

1. Step 1: Write the proportion equation
   21,990.72 : 30,348.18 = 15,624.12 : x
2. Step 2: Convert to fraction form
   21,990.72/30,348.18 = 15,624.12/x
3. Step 3: Cross multiply
   21,990.72x = 30,348.18 × 15,624.12
4. Step 4: Simplify right side
   21,990.72x = 474,163,606.10
5. Step 5: Solve for x
   x = 474,163,606.10/21,990.72
6. Step 6: Final answer
   x = 21,561.99