Finding the Fourth Proportional to 2,156.20, 2,973.74 and 1,399.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,156.20 : 2,973.74 = 1,399.10 : x
2. Step 2: Convert to fraction form
   2,156.20/2,973.74 = 1,399.10/x
3. Step 3: Cross multiply
   2,156.20x = 2,973.74 × 1,399.10
4. Step 4: Simplify right side
   2,156.20x = 4,160,559.63
5. Step 5: Solve for x
   x = 4,160,559.63/2,156.20
6. Step 6: Final answer
   x = 1,929.58