Finding the Fourth Proportional to 1,138.37, 1,570.73 and 718.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,138.37 : 1,570.73 = 718.79 : x
2. Step 2: Convert to fraction form
   1,138.37/1,570.73 = 718.79/x
3. Step 3: Cross multiply
   1,138.37x = 1,570.73 × 718.79
4. Step 4: Simplify right side
   1,138.37x = 1,129,013.57
5. Step 5: Solve for x
   x = 1,129,013.57/1,138.37
6. Step 6: Final answer
   x = 991.79