Finding the Fourth Proportional to 1,373.76, 2,064.96 and 990.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,373.76 : 2,064.96 = 990.72 : x
2. Step 2: Convert to fraction form
   1,373.76/2,064.96 = 990.72/x
3. Step 3: Cross multiply
   1,373.76x = 2,064.96 × 990.72
4. Step 4: Simplify right side
   1,373.76x = 2,045,797.17
5. Step 5: Solve for x
   x = 2,045,797.17/1,373.76
6. Step 6: Final answer
   x = 1,489.20