Finding the Fourth Proportional to 1,390.03, 1,916.81 and 1,191.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.03 : 1,916.81 = 1,191.56 : x
2. Step 2: Convert to fraction form
   1,390.03/1,916.81 = 1,191.56/x
3. Step 3: Cross multiply
   1,390.03x = 1,916.81 × 1,191.56
4. Step 4: Simplify right side
   1,390.03x = 2,284,000.53
5. Step 5: Solve for x
   x = 2,284,000.53/1,390.03
6. Step 6: Final answer
   x = 1,643.13