Finding the Fourth Proportional to 12,155.72, 16,779.06 and 7,121.56

Step by Step Solution

1. Step 1: Write the proportion equation
   12,155.72 : 16,779.06 = 7,121.56 : x
2. Step 2: Convert to fraction form
   12,155.72/16,779.06 = 7,121.56/x
3. Step 3: Cross multiply
   12,155.72x = 16,779.06 × 7,121.56
4. Step 4: Simplify right side
   12,155.72x = 119,493,082.53
5. Step 5: Solve for x
   x = 119,493,082.53/12,155.72
6. Step 6: Final answer
   x = 9,830.19