Finding the Fourth Proportional to 1,380.24, 2,066.16 and 990.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.24 : 2,066.16 = 990.72 : x
2. Step 2: Convert to fraction form
   1,380.24/2,066.16 = 990.72/x
3. Step 3: Cross multiply
   1,380.24x = 2,066.16 × 990.72
4. Step 4: Simplify right side
   1,380.24x = 2,046,986.04
5. Step 5: Solve for x
   x = 2,046,986.04/1,380.24
6. Step 6: Final answer
   x = 1,483.07