Finding the Fourth Proportional to 1,536.78, 2,120.75 and 838.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,536.78 : 2,120.75 = 838.15 : x
2. Step 2: Convert to fraction form
   1,536.78/2,120.75 = 838.15/x
3. Step 3: Cross multiply
   1,536.78x = 2,120.75 × 838.15
4. Step 4: Simplify right side
   1,536.78x = 1,777,508.22
5. Step 5: Solve for x
   x = 1,777,508.22/1,536.78
6. Step 6: Final answer
   x = 1,156.65