Finding the Fourth Proportional to 1,405.10, 1,938.83 and 815.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.10 : 1,938.83 = 815.67 : x
2. Step 2: Convert to fraction form
   1,405.10/1,938.83 = 815.67/x
3. Step 3: Cross multiply
   1,405.10x = 1,938.83 × 815.67
4. Step 4: Simplify right side
   1,405.10x = 1,581,441.39
5. Step 5: Solve for x
   x = 1,581,441.39/1,405.10
6. Step 6: Final answer
   x = 1,125.50