Finding the Fourth Proportional to 1,550.70, 2,139.33 and 991.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,550.70 : 2,139.33 = 991.02 : x
2. Step 2: Convert to fraction form
   1,550.70/2,139.33 = 991.02/x
3. Step 3: Cross multiply
   1,550.70x = 2,139.33 × 991.02
4. Step 4: Simplify right side
   1,550.70x = 2,120,118.82
5. Step 5: Solve for x
   x = 2,120,118.82/1,550.70
6. Step 6: Final answer
   x = 1,367.20