Finding the Fourth Proportional to 2,166.72, 2,990.06 and 1,171.99

Step by Step Solution

1. Step 1: Write the proportion equation
   2,166.72 : 2,990.06 = 1,171.99 : x
2. Step 2: Convert to fraction form
   2,166.72/2,990.06 = 1,171.99/x
3. Step 3: Cross multiply
   2,166.72x = 2,990.06 × 1,171.99
4. Step 4: Simplify right side
   2,166.72x = 3,504,320.42
5. Step 5: Solve for x
   x = 3,504,320.42/2,166.72
6. Step 6: Final answer
   x = 1,617.34