Finding the Fourth Proportional to 2,160.28, 2,981.05 and 1,215.91

Step by Step Solution

1. Step 1: Write the proportion equation
   2,160.28 : 2,981.05 = 1,215.91 : x
2. Step 2: Convert to fraction form
   2,160.28/2,981.05 = 1,215.91/x
3. Step 3: Cross multiply
   2,160.28x = 2,981.05 × 1,215.91
4. Step 4: Simplify right side
   2,160.28x = 3,624,688.51
5. Step 5: Solve for x
   x = 3,624,688.51/2,160.28
6. Step 6: Final answer
   x = 1,677.88