Finding the Fourth Proportional to 1,336.72, 2,005.34 and 412.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,336.72 : 2,005.34 = 412.12 : x
2. Step 2: Convert to fraction form
   1,336.72/2,005.34 = 412.12/x
3. Step 3: Cross multiply
   1,336.72x = 2,005.34 × 412.12
4. Step 4: Simplify right side
   1,336.72x = 826,440.72
5. Step 5: Solve for x
   x = 826,440.72/1,336.72
6. Step 6: Final answer
   x = 618.26