Finding the Fourth Proportional to 1,393.10, 1,919.24 and 972.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,393.10 : 1,919.24 = 972.72 : x
2. Step 2: Convert to fraction form
   1,393.10/1,919.24 = 972.72/x
3. Step 3: Cross multiply
   1,393.10x = 1,919.24 × 972.72
4. Step 4: Simplify right side
   1,393.10x = 1,866,883.13
5. Step 5: Solve for x
   x = 1,866,883.13/1,393.10
6. Step 6: Final answer
   x = 1,340.09