Finding the Fourth Proportional to 1,395.89, 1,926.35 and 766.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,395.89 : 1,926.35 = 766.40 : x
2. Step 2: Convert to fraction form
   1,395.89/1,926.35 = 766.40/x
3. Step 3: Cross multiply
   1,395.89x = 1,926.35 × 766.40
4. Step 4: Simplify right side
   1,395.89x = 1,476,354.64
5. Step 5: Solve for x
   x = 1,476,354.64/1,395.89
6. Step 6: Final answer
   x = 1,057.64