Finding the Fourth Proportional to 2,155.91, 2,975.06 and 1,211.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,155.91 : 2,975.06 = 1,211.72 : x
2. Step 2: Convert to fraction form
   2,155.91/2,975.06 = 1,211.72/x
3. Step 3: Cross multiply
   2,155.91x = 2,975.06 × 1,211.72
4. Step 4: Simplify right side
   2,155.91x = 3,604,927.86
5. Step 5: Solve for x
   x = 3,604,927.86/2,155.91
6. Step 6: Final answer
   x = 1,672.12