Finding the Fourth Proportional to 2,111.79, 2,912.60 and 1,970.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.79 : 2,912.60 = 1,970.31 : x
2. Step 2: Convert to fraction form
   2,111.79/2,912.60 = 1,970.31/x
3. Step 3: Cross multiply
   2,111.79x = 2,912.60 × 1,970.31
4. Step 4: Simplify right side
   2,111.79x = 5,738,724.91
5. Step 5: Solve for x
   x = 5,738,724.91/2,111.79
6. Step 6: Final answer
   x = 2,717.47