Finding the Fourth Proportional to 2,781.32, 4,172.31 and 1,320.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,781.32 : 4,172.31 = 1,320.12 : x
2. Step 2: Convert to fraction form
   2,781.32/4,172.31 = 1,320.12/x
3. Step 3: Cross multiply
   2,781.32x = 4,172.31 × 1,320.12
4. Step 4: Simplify right side
   2,781.32x = 5,507,949.88
5. Step 5: Solve for x
   x = 5,507,949.88/2,781.32
6. Step 6: Final answer
   x = 1,980.34