Finding the Fourth Proportional to 1,361.72, 1,878.68 and 830.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,361.72 : 1,878.68 = 830.38 : x
2. Step 2: Convert to fraction form
   1,361.72/1,878.68 = 830.38/x
3. Step 3: Cross multiply
   1,361.72x = 1,878.68 × 830.38
4. Step 4: Simplify right side
   1,361.72x = 1,560,018.30
5. Step 5: Solve for x
   x = 1,560,018.30/1,361.72
6. Step 6: Final answer
   x = 1,145.62