Finding the Fourth Proportional to 1,371.77, 1,891.99 and 840.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,371.77 : 1,891.99 = 840.07 : x
2. Step 2: Convert to fraction form
   1,371.77/1,891.99 = 840.07/x
3. Step 3: Cross multiply
   1,371.77x = 1,891.99 × 840.07
4. Step 4: Simplify right side
   1,371.77x = 1,589,407.45
5. Step 5: Solve for x
   x = 1,589,407.45/1,371.77
6. Step 6: Final answer
   x = 1,158.66