Finding the Fourth Proportional to 1,412.80, 1,949.76 and 815.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,412.80 : 1,949.76 = 815.50 : x
2. Step 2: Convert to fraction form
   1,412.80/1,949.76 = 815.50/x
3. Step 3: Cross multiply
   1,412.80x = 1,949.76 × 815.50
4. Step 4: Simplify right side
   1,412.80x = 1,590,029.28
5. Step 5: Solve for x
   x = 1,590,029.28/1,412.80
6. Step 6: Final answer
   x = 1,125.45