Finding the Fourth Proportional to 1,112.88, 1,670.22 and 678.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,112.88 : 1,670.22 = 678.72 : x
2. Step 2: Convert to fraction form
   1,112.88/1,670.22 = 678.72/x
3. Step 3: Cross multiply
   1,112.88x = 1,670.22 × 678.72
4. Step 4: Simplify right side
   1,112.88x = 1,133,611.72
5. Step 5: Solve for x
   x = 1,133,611.72/1,112.88
6. Step 6: Final answer
   x = 1,018.63