Finding the Fourth Proportional to 1,428.96, 1,972.20 and 839.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.96 : 1,972.20 = 839.52 : x
2. Step 2: Convert to fraction form
   1,428.96/1,972.20 = 839.52/x
3. Step 3: Cross multiply
   1,428.96x = 1,972.20 × 839.52
4. Step 4: Simplify right side
   1,428.96x = 1,655,701.34
5. Step 5: Solve for x
   x = 1,655,701.34/1,428.96
6. Step 6: Final answer
   x = 1,158.68