Finding the Fourth Proportional to 2,635.40, 3,950.78 and 991.52

Step by Step Solution

1. Step 1: Write the proportion equation
   2,635.40 : 3,950.78 = 991.52 : x
2. Step 2: Convert to fraction form
   2,635.40/3,950.78 = 991.52/x
3. Step 3: Cross multiply
   2,635.40x = 3,950.78 × 991.52
4. Step 4: Simplify right side
   2,635.40x = 3,917,277.39
5. Step 5: Solve for x
   x = 3,917,277.39/2,635.40
6. Step 6: Final answer
   x = 1,486.41