Finding the Fourth Proportional to 1,388.52, 1,906.12 and 1,191.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.52 : 1,906.12 = 1,191.69 : x
2. Step 2: Convert to fraction form
   1,388.52/1,906.12 = 1,191.69/x
3. Step 3: Cross multiply
   1,388.52x = 1,906.12 × 1,191.69
4. Step 4: Simplify right side
   1,388.52x = 2,271,504.14
5. Step 5: Solve for x
   x = 2,271,504.14/1,388.52
6. Step 6: Final answer
   x = 1,635.92