Finding the Fourth Proportional to 12,956.38, 19,428.18 and 5,458.57

Step by Step Solution

1. Step 1: Write the proportion equation
   12,956.38 : 19,428.18 = 5,458.57 : x
2. Step 2: Convert to fraction form
   12,956.38/19,428.18 = 5,458.57/x
3. Step 3: Cross multiply
   12,956.38x = 19,428.18 × 5,458.57
4. Step 4: Simplify right side
   12,956.38x = 106,050,080.50
5. Step 5: Solve for x
   x = 106,050,080.50/12,956.38
6. Step 6: Final answer
   x = 8,185.16