Finding the Fourth Proportional to 2,111.57, 2,913.96 and 1,215.37

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.57 : 2,913.96 = 1,215.37 : x
2. Step 2: Convert to fraction form
   2,111.57/2,913.96 = 1,215.37/x
3. Step 3: Cross multiply
   2,111.57x = 2,913.96 × 1,215.37
4. Step 4: Simplify right side
   2,111.57x = 3,541,539.57
5. Step 5: Solve for x
   x = 3,541,539.57/2,111.57
6. Step 6: Final answer
   x = 1,677.21