Finding the Fourth Proportional to 1,890.72, 2,837.05 and 780.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,890.72 : 2,837.05 = 780.96 : x
2. Step 2: Convert to fraction form
   1,890.72/2,837.05 = 780.96/x
3. Step 3: Cross multiply
   1,890.72x = 2,837.05 × 780.96
4. Step 4: Simplify right side
   1,890.72x = 2,215,622.57
5. Step 5: Solve for x
   x = 2,215,622.57/1,890.72
6. Step 6: Final answer
   x = 1,171.84