Finding the Fourth Proportional to 1,311.30, 1,810.69 and 1,171.17

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.30 : 1,810.69 = 1,171.17 : x
2. Step 2: Convert to fraction form
   1,311.30/1,810.69 = 1,171.17/x
3. Step 3: Cross multiply
   1,311.30x = 1,810.69 × 1,171.17
4. Step 4: Simplify right side
   1,311.30x = 2,120,622.88
5. Step 5: Solve for x
   x = 2,120,622.88/1,311.30
6. Step 6: Final answer
   x = 1,617.19