Finding the Fourth Proportional to 1,397.47, 1,928.60 and 776.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.47 : 1,928.60 = 776.47 : x
2. Step 2: Convert to fraction form
   1,397.47/1,928.60 = 776.47/x
3. Step 3: Cross multiply
   1,397.47x = 1,928.60 × 776.47
4. Step 4: Simplify right side
   1,397.47x = 1,497,500.04
5. Step 5: Solve for x
   x = 1,497,500.04/1,397.47
6. Step 6: Final answer
   x = 1,071.58