Finding the Fourth Proportional to 2,109.57, 2,911.71 and 1,213.81

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.57 : 2,911.71 = 1,213.81 : x
2. Step 2: Convert to fraction form
   2,109.57/2,911.71 = 1,213.81/x
3. Step 3: Cross multiply
   2,109.57x = 2,911.71 × 1,213.81
4. Step 4: Simplify right side
   2,109.57x = 3,534,262.72
5. Step 5: Solve for x
   x = 3,534,262.72/2,109.57
6. Step 6: Final answer
   x = 1,675.35