Finding the Fourth Proportional to 2,156.79, 2,976.21 and 1,212.45

Step by Step Solution

1. Step 1: Write the proportion equation
   2,156.79 : 2,976.21 = 1,212.45 : x
2. Step 2: Convert to fraction form
   2,156.79/2,976.21 = 1,212.45/x
3. Step 3: Cross multiply
   2,156.79x = 2,976.21 × 1,212.45
4. Step 4: Simplify right side
   2,156.79x = 3,608,505.81
5. Step 5: Solve for x
   x = 3,608,505.81/2,156.79
6. Step 6: Final answer
   x = 1,673.09