Finding the Fourth Proportional to 1,399.77, 1,931.68 and 770.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.77 : 1,931.68 = 770.30 : x
2. Step 2: Convert to fraction form
   1,399.77/1,931.68 = 770.30/x
3. Step 3: Cross multiply
   1,399.77x = 1,931.68 × 770.30
4. Step 4: Simplify right side
   1,399.77x = 1,487,973.10
5. Step 5: Solve for x
   x = 1,487,973.10/1,399.77
6. Step 6: Final answer
   x = 1,063.01