Finding the Fourth Proportional to 13,211.57, 19,812.78 and 5,311.76

Step by Step Solution

1. Step 1: Write the proportion equation
   13,211.57 : 19,812.78 = 5,311.76 : x
2. Step 2: Convert to fraction form
   13,211.57/19,812.78 = 5,311.76/x
3. Step 3: Cross multiply
   13,211.57x = 19,812.78 × 5,311.76
4. Step 4: Simplify right side
   13,211.57x = 105,240,633.23
5. Step 5: Solve for x
   x = 105,240,633.23/13,211.57
6. Step 6: Final answer
   x = 7,965.79