Finding the Fourth Proportional to 1,173.72, 1,620.50 and 815.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,173.72 : 1,620.50 = 815.48 : x
2. Step 2: Convert to fraction form
   1,173.72/1,620.50 = 815.48/x
3. Step 3: Cross multiply
   1,173.72x = 1,620.50 × 815.48
4. Step 4: Simplify right side
   1,173.72x = 1,321,485.34
5. Step 5: Solve for x
   x = 1,321,485.34/1,173.72
6. Step 6: Final answer
   x = 1,125.89