Finding the Fourth Proportional to 11,449.31, 17,151.61 and 7,890.80

Step by Step Solution

1. Step 1: Write the proportion equation
   11,449.31 : 17,151.61 = 7,890.80 : x
2. Step 2: Convert to fraction form
   11,449.31/17,151.61 = 7,890.80/x
3. Step 3: Cross multiply
   11,449.31x = 17,151.61 × 7,890.80
4. Step 4: Simplify right side
   11,449.31x = 135,339,811.31
5. Step 5: Solve for x
   x = 135,339,811.31/11,449.31
6. Step 6: Final answer
   x = 11,820.78