Finding the Fourth Proportional to 2,156.78, 2,976.26 and 1,212.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,156.78 : 2,976.26 = 1,212.72 : x
2. Step 2: Convert to fraction form
   2,156.78/2,976.26 = 1,212.72/x
3. Step 3: Cross multiply
   2,156.78x = 2,976.26 × 1,212.72
4. Step 4: Simplify right side
   2,156.78x = 3,609,371.25
5. Step 5: Solve for x
   x = 3,609,371.25/2,156.78
6. Step 6: Final answer
   x = 1,673.50