Finding the Fourth Proportional to 1,150.98, 1,725.96 and 420.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,150.98 : 1,725.96 = 420.05 : x
2. Step 2: Convert to fraction form
   1,150.98/1,725.96 = 420.05/x
3. Step 3: Cross multiply
   1,150.98x = 1,725.96 × 420.05
4. Step 4: Simplify right side
   1,150.98x = 724,984.50
5. Step 5: Solve for x
   x = 724,984.50/1,150.98
6. Step 6: Final answer
   x = 629.88