Finding the Fourth Proportional to 1,372.42, 1,891.44 and 1,213.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,372.42 : 1,891.44 = 1,213.12 : x
2. Step 2: Convert to fraction form
   1,372.42/1,891.44 = 1,213.12/x
3. Step 3: Cross multiply
   1,372.42x = 1,891.44 × 1,213.12
4. Step 4: Simplify right side
   1,372.42x = 2,294,543.69
5. Step 5: Solve for x
   x = 2,294,543.69/1,372.42
6. Step 6: Final answer
   x = 1,671.90