Finding the Fourth Proportional to 2,142.80, 2,956.56 and 1,211.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,142.80 : 2,956.56 = 1,211.12 : x
2. Step 2: Convert to fraction form
   2,142.80/2,956.56 = 1,211.12/x
3. Step 3: Cross multiply
   2,142.80x = 2,956.56 × 1,211.12
4. Step 4: Simplify right side
   2,142.80x = 3,580,748.95
5. Step 5: Solve for x
   x = 3,580,748.95/2,142.80
6. Step 6: Final answer
   x = 1,671.06