Finding the Fourth Proportional to 1,385.65, 1,912.23 and 788.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.65 : 1,912.23 = 788.24 : x
2. Step 2: Convert to fraction form
   1,385.65/1,912.23 = 788.24/x
3. Step 3: Cross multiply
   1,385.65x = 1,912.23 × 788.24
4. Step 4: Simplify right side
   1,385.65x = 1,507,300.96
5. Step 5: Solve for x
   x = 1,507,300.96/1,385.65
6. Step 6: Final answer
   x = 1,087.80