Finding the Fourth Proportional to 912.72, 1,258.16 and 715.89

Step by Step Solution

1. Step 1: Write the proportion equation
   912.72 : 1,258.16 = 715.89 : x
2. Step 2: Convert to fraction form
   912.72/1,258.16 = 715.89/x
3. Step 3: Cross multiply
   912.72x = 1,258.16 × 715.89
4. Step 4: Simplify right side
   912.72x = 900,704.16
5. Step 5: Solve for x
   x = 900,704.16/912.72
6. Step 6: Final answer
   x = 986.84