Finding the Fourth Proportional to 1,378.32, 2,055.18 and 1,320.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.32 : 2,055.18 = 1,320.72 : x
2. Step 2: Convert to fraction form
   1,378.32/2,055.18 = 1,320.72/x
3. Step 3: Cross multiply
   1,378.32x = 2,055.18 × 1,320.72
4. Step 4: Simplify right side
   1,378.32x = 2,714,317.33
5. Step 5: Solve for x
   x = 2,714,317.33/1,378.32
6. Step 6: Final answer
   x = 1,969.29