Finding the Fourth Proportional to 978.82, 1,471.10 and 815.33

Step by Step Solution

1. Step 1: Write the proportion equation
   978.82 : 1,471.10 = 815.33 : x
2. Step 2: Convert to fraction form
   978.82/1,471.10 = 815.33/x
3. Step 3: Cross multiply
   978.82x = 1,471.10 × 815.33
4. Step 4: Simplify right side
   978.82x = 1,199,431.56
5. Step 5: Solve for x
   x = 1,199,431.56/978.82
6. Step 6: Final answer
   x = 1,225.39