Finding the Fourth Proportional to 1,968.40, 2,715.72 and 1,129.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,968.40 : 2,715.72 = 1,129.12 : x
2. Step 2: Convert to fraction form
   1,968.40/2,715.72 = 1,129.12/x
3. Step 3: Cross multiply
   1,968.40x = 2,715.72 × 1,129.12
4. Step 4: Simplify right side
   1,968.40x = 3,066,373.77
5. Step 5: Solve for x
   x = 3,066,373.77/1,968.40
6. Step 6: Final answer
   x = 1,557.80