Finding the Fourth Proportional to 12,861.81, 17,751.83 and 8,142.75

Step by Step Solution

1. Step 1: Write the proportion equation
   12,861.81 : 17,751.83 = 8,142.75 : x
2. Step 2: Convert to fraction form
   12,861.81/17,751.83 = 8,142.75/x
3. Step 3: Cross multiply
   12,861.81x = 17,751.83 × 8,142.75
4. Step 4: Simplify right side
   12,861.81x = 144,548,673.02
5. Step 5: Solve for x
   x = 144,548,673.02/12,861.81
6. Step 6: Final answer
   x = 11,238.59