Finding the Fourth Proportional to 12,815.96, 17,687.24 and 7,779.02

Step by Step Solution

1. Step 1: Write the proportion equation
   12,815.96 : 17,687.24 = 7,779.02 : x
2. Step 2: Convert to fraction form
   12,815.96/17,687.24 = 7,779.02/x
3. Step 3: Cross multiply
   12,815.96x = 17,687.24 × 7,779.02
4. Step 4: Simplify right side
   12,815.96x = 137,589,457.37
5. Step 5: Solve for x
   x = 137,589,457.37/12,815.96
6. Step 6: Final answer
   x = 10,735.79