Finding the Fourth Proportional to 1,428.02, 1,971.31 and 838.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.02 : 1,971.31 = 838.59 : x
2. Step 2: Convert to fraction form
   1,428.02/1,971.31 = 838.59/x
3. Step 3: Cross multiply
   1,428.02x = 1,971.31 × 838.59
4. Step 4: Simplify right side
   1,428.02x = 1,653,129.29
5. Step 5: Solve for x
   x = 1,653,129.29/1,428.02
6. Step 6: Final answer
   x = 1,157.64