Finding the Fourth Proportional to 1,238.06, 1,710.18 and 991.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.06 : 1,710.18 = 991.10 : x
2. Step 2: Convert to fraction form
   1,238.06/1,710.18 = 991.10/x
3. Step 3: Cross multiply
   1,238.06x = 1,710.18 × 991.10
4. Step 4: Simplify right side
   1,238.06x = 1,694,950.85
5. Step 5: Solve for x
   x = 1,694,950.85/1,238.06
6. Step 6: Final answer
   x = 1,369.04