Finding the Fourth Proportional to 10,996.78, 15,155.20 and 7,810.21

Step by Step Solution

1. Step 1: Write the proportion equation
   10,996.78 : 15,155.20 = 7,810.21 : x
2. Step 2: Convert to fraction form
   10,996.78/15,155.20 = 7,810.21/x
3. Step 3: Cross multiply
   10,996.78x = 15,155.20 × 7,810.21
4. Step 4: Simplify right side
   10,996.78x = 118,365,313.54
5. Step 5: Solve for x
   x = 118,365,313.54/10,996.78
6. Step 6: Final answer
   x = 10,763.64