Finding the Fourth Proportional to 2,160.90, 2,981.51 and 1,216.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,160.90 : 2,981.51 = 1,216.50 : x
2. Step 2: Convert to fraction form
   2,160.90/2,981.51 = 1,216.50/x
3. Step 3: Cross multiply
   2,160.90x = 2,981.51 × 1,216.50
4. Step 4: Simplify right side
   2,160.90x = 3,627,000.83
5. Step 5: Solve for x
   x = 3,627,000.83/2,160.90
6. Step 6: Final answer
   x = 1,678.47