Finding the Fourth Proportional to 1,288.68, 1,777.52 and 791.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.68 : 1,777.52 = 791.10 : x
2. Step 2: Convert to fraction form
   1,288.68/1,777.52 = 791.10/x
3. Step 3: Cross multiply
   1,288.68x = 1,777.52 × 791.10
4. Step 4: Simplify right side
   1,288.68x = 1,406,196.07
5. Step 5: Solve for x
   x = 1,406,196.07/1,288.68
6. Step 6: Final answer
   x = 1,091.19