Finding the Fourth Proportional to 931.82, 1,392.71 and 813.76

Step by Step Solution

1. Step 1: Write the proportion equation
   931.82 : 1,392.71 = 813.76 : x
2. Step 2: Convert to fraction form
   931.82/1,392.71 = 813.76/x
3. Step 3: Cross multiply
   931.82x = 1,392.71 × 813.76
4. Step 4: Simplify right side
   931.82x = 1,133,336.55
5. Step 5: Solve for x
   x = 1,133,336.55/931.82
6. Step 6: Final answer
   x = 1,216.26