Finding the Fourth Proportional to 1,911.67, 2,868.72 and 816.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,911.67 : 2,868.72 = 816.05 : x
2. Step 2: Convert to fraction form
   1,911.67/2,868.72 = 816.05/x
3. Step 3: Cross multiply
   1,911.67x = 2,868.72 × 816.05
4. Step 4: Simplify right side
   1,911.67x = 2,341,007.67
5. Step 5: Solve for x
   x = 2,341,007.67/1,911.67
6. Step 6: Final answer
   x = 1,224.59