Finding the Fourth Proportional to 13,311.99, 19,981.20 and 7,072.05

Step by Step Solution

1. Step 1: Write the proportion equation
   13,311.99 : 19,981.20 = 7,072.05 : x
2. Step 2: Convert to fraction form
   13,311.99/19,981.20 = 7,072.05/x
3. Step 3: Cross multiply
   13,311.99x = 19,981.20 × 7,072.05
4. Step 4: Simplify right side
   13,311.99x = 141,308,045.46
5. Step 5: Solve for x
   x = 141,308,045.46/13,311.99
6. Step 6: Final answer
   x = 10,615.10