Finding the Fourth Proportional to 2,111.76, 3,166.92 and 813.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.76 : 3,166.92 = 813.12 : x
2. Step 2: Convert to fraction form
   2,111.76/3,166.92 = 813.12/x
3. Step 3: Cross multiply
   2,111.76x = 3,166.92 × 813.12
4. Step 4: Simplify right side
   2,111.76x = 2,575,085.99
5. Step 5: Solve for x
   x = 2,575,085.99/2,111.76
6. Step 6: Final answer
   x = 1,219.40