Finding the Fourth Proportional to 1,290.42, 1,780.83 and 847.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.42 : 1,780.83 = 847.98 : x
2. Step 2: Convert to fraction form
   1,290.42/1,780.83 = 847.98/x
3. Step 3: Cross multiply
   1,290.42x = 1,780.83 × 847.98
4. Step 4: Simplify right side
   1,290.42x = 1,510,108.22
5. Step 5: Solve for x
   x = 1,510,108.22/1,290.42
6. Step 6: Final answer
   x = 1,170.25