Finding the Fourth Proportional to 1,131.78, 1,697.48 and 309.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.78 : 1,697.48 = 309.91 : x
2. Step 2: Convert to fraction form
   1,131.78/1,697.48 = 309.91/x
3. Step 3: Cross multiply
   1,131.78x = 1,697.48 × 309.91
4. Step 4: Simplify right side
   1,131.78x = 526,065.45
5. Step 5: Solve for x
   x = 526,065.45/1,131.78
6. Step 6: Final answer
   x = 464.81