Finding the Fourth Proportional to 1,427.79, 1,970.33 and 838.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,427.79 : 1,970.33 = 838.21 : x
2. Step 2: Convert to fraction form
   1,427.79/1,970.33 = 838.21/x
3. Step 3: Cross multiply
   1,427.79x = 1,970.33 × 838.21
4. Step 4: Simplify right side
   1,427.79x = 1,651,536.27
5. Step 5: Solve for x
   x = 1,651,536.27/1,427.79
6. Step 6: Final answer
   x = 1,156.71