Finding the Fourth Proportional to 13,128.23, 18,116.52 and 7,820.30

Step by Step Solution

1. Step 1: Write the proportion equation
   13,128.23 : 18,116.52 = 7,820.30 : x
2. Step 2: Convert to fraction form
   13,128.23/18,116.52 = 7,820.30/x
3. Step 3: Cross multiply
   13,128.23x = 18,116.52 × 7,820.30
4. Step 4: Simplify right side
   13,128.23x = 141,676,621.36
5. Step 5: Solve for x
   x = 141,676,621.36/13,128.23
6. Step 6: Final answer
   x = 10,791.75