Finding the Fourth Proportional to 2,128.61, 3,185.80 and 1,190.05

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.61 : 3,185.80 = 1,190.05 : x
2. Step 2: Convert to fraction form
   2,128.61/3,185.80 = 1,190.05/x
3. Step 3: Cross multiply
   2,128.61x = 3,185.80 × 1,190.05
4. Step 4: Simplify right side
   2,128.61x = 3,791,250.35
5. Step 5: Solve for x
   x = 3,791,250.35/2,128.61
6. Step 6: Final answer
   x = 1,781.09