Finding the Fourth Proportional to 1,431.72, 1,976.18 and 842.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.72 : 1,976.18 = 842.45 : x
2. Step 2: Convert to fraction form
   1,431.72/1,976.18 = 842.45/x
3. Step 3: Cross multiply
   1,431.72x = 1,976.18 × 842.45
4. Step 4: Simplify right side
   1,431.72x = 1,664,818.75
5. Step 5: Solve for x
   x = 1,664,818.75/1,431.72
6. Step 6: Final answer
   x = 1,162.81