Finding the Fourth Proportional to 1,407.64, 2,112.56 and 920.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.64 : 2,112.56 = 920.56 : x
2. Step 2: Convert to fraction form
   1,407.64/2,112.56 = 920.56/x
3. Step 3: Cross multiply
   1,407.64x = 2,112.56 × 920.56
4. Step 4: Simplify right side
   1,407.64x = 1,944,738.23
5. Step 5: Solve for x
   x = 1,944,738.23/1,407.64
6. Step 6: Final answer
   x = 1,381.56