Finding the Fourth Proportional to 1,380.15, 2,072.58 and 920.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.15 : 2,072.58 = 920.88 : x
2. Step 2: Convert to fraction form
   1,380.15/2,072.58 = 920.88/x
3. Step 3: Cross multiply
   1,380.15x = 2,072.58 × 920.88
4. Step 4: Simplify right side
   1,380.15x = 1,908,597.47
5. Step 5: Solve for x
   x = 1,908,597.47/1,380.15
6. Step 6: Final answer
   x = 1,382.89