Finding the Fourth Proportional to 1,401.74, 2,100.72 and 989.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.74 : 2,100.72 = 989.90 : x
2. Step 2: Convert to fraction form
   1,401.74/2,100.72 = 989.90/x
3. Step 3: Cross multiply
   1,401.74x = 2,100.72 × 989.90
4. Step 4: Simplify right side
   1,401.74x = 2,079,502.73
5. Step 5: Solve for x
   x = 2,079,502.73/1,401.74
6. Step 6: Final answer
   x = 1,483.52