Finding the Fourth Proportional to 13,200.48, 18,213.54 and 7,820.20

Step by Step Solution

1. Step 1: Write the proportion equation
   13,200.48 : 18,213.54 = 7,820.20 : x
2. Step 2: Convert to fraction form
   13,200.48/18,213.54 = 7,820.20/x
3. Step 3: Cross multiply
   13,200.48x = 18,213.54 × 7,820.20
4. Step 4: Simplify right side
   13,200.48x = 142,433,525.51
5. Step 5: Solve for x
   x = 142,433,525.51/13,200.48
6. Step 6: Final answer
   x = 10,790.03