Finding the Fourth Proportional to 1,391.25, 1,920.05 and 770.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.25 : 1,920.05 = 770.37 : x
2. Step 2: Convert to fraction form
   1,391.25/1,920.05 = 770.37/x
3. Step 3: Cross multiply
   1,391.25x = 1,920.05 × 770.37
4. Step 4: Simplify right side
   1,391.25x = 1,479,145.07
5. Step 5: Solve for x
   x = 1,479,145.07/1,391.25
6. Step 6: Final answer
   x = 1,063.18