Finding the Fourth Proportional to 23,172.81, 31,978.74 and 13,613.10

Step by Step Solution

1. Step 1: Write the proportion equation
   23,172.81 : 31,978.74 = 13,613.10 : x
2. Step 2: Convert to fraction form
   23,172.81/31,978.74 = 13,613.10/x
3. Step 3: Cross multiply
   23,172.81x = 31,978.74 × 13,613.10
4. Step 4: Simplify right side
   23,172.81x = 435,329,865.84
5. Step 5: Solve for x
   x = 435,329,865.84/23,172.81
6. Step 6: Final answer
   x = 18,786.23