Finding the Fourth Proportional to 1,405.69, 1,939.98 and 776.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.69 : 1,939.98 = 776.28 : x
2. Step 2: Convert to fraction form
   1,405.69/1,939.98 = 776.28/x
3. Step 3: Cross multiply
   1,405.69x = 1,939.98 × 776.28
4. Step 4: Simplify right side
   1,405.69x = 1,505,967.67
5. Step 5: Solve for x
   x = 1,505,967.67/1,405.69
6. Step 6: Final answer
   x = 1,071.34