Finding the Fourth Proportional to 1,400.30, 1,931.85 and 840.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,400.30 : 1,931.85 = 840.80 : x
2. Step 2: Convert to fraction form
   1,400.30/1,931.85 = 840.80/x
3. Step 3: Cross multiply
   1,400.30x = 1,931.85 × 840.80
4. Step 4: Simplify right side
   1,400.30x = 1,624,289.82
5. Step 5: Solve for x
   x = 1,624,289.82/1,400.30
6. Step 6: Final answer
   x = 1,159.96