Finding the Fourth Proportional to 1,200.37, 1,800.57 and 420.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,200.37 : 1,800.57 = 420.34 : x
2. Step 2: Convert to fraction form
   1,200.37/1,800.57 = 420.34/x
3. Step 3: Cross multiply
   1,200.37x = 1,800.57 × 420.34
4. Step 4: Simplify right side
   1,200.37x = 756,851.59
5. Step 5: Solve for x
   x = 756,851.59/1,200.37
6. Step 6: Final answer
   x = 630.52