Finding the Fourth Proportional to 13,642.02, 18,829.80 and 7,978.50

Step by Step Solution

1. Step 1: Write the proportion equation
   13,642.02 : 18,829.80 = 7,978.50 : x
2. Step 2: Convert to fraction form
   13,642.02/18,829.80 = 7,978.50/x
3. Step 3: Cross multiply
   13,642.02x = 18,829.80 × 7,978.50
4. Step 4: Simplify right side
   13,642.02x = 150,233,559.30
5. Step 5: Solve for x
   x = 150,233,559.30/13,642.02
6. Step 6: Final answer
   x = 11,012.56