Finding the Fourth Proportional to 2,160.71, 2,981.72 and 1,216.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,160.71 : 2,981.72 = 1,216.56 : x
2. Step 2: Convert to fraction form
   2,160.71/2,981.72 = 1,216.56/x
3. Step 3: Cross multiply
   2,160.71x = 2,981.72 × 1,216.56
4. Step 4: Simplify right side
   2,160.71x = 3,627,435.20
5. Step 5: Solve for x
   x = 3,627,435.20/2,160.71
6. Step 6: Final answer
   x = 1,678.82