Finding the Fourth Proportional to 20,796.83, 31,176.61 and 7,640

Step by Step Solution

1. Step 1: Write the proportion equation
   20,796.83 : 31,176.61 = 7,640 : x
2. Step 2: Convert to fraction form
   20,796.83/31,176.61 = 7,640/x
3. Step 3: Cross multiply
   20,796.83x = 31,176.61 × 7,640
4. Step 4: Simplify right side
   20,796.83x = 238,189,300.40
5. Step 5: Solve for x
   x = 238,189,300.40/20,796.83
6. Step 6: Final answer
   x = 11,453.15