Finding the Fourth Proportional to 1,370.12, 1,890.63 and 780.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,370.12 : 1,890.63 = 780.62 : x
2. Step 2: Convert to fraction form
   1,370.12/1,890.63 = 780.62/x
3. Step 3: Cross multiply
   1,370.12x = 1,890.63 × 780.62
4. Step 4: Simplify right side
   1,370.12x = 1,475,863.59
5. Step 5: Solve for x
   x = 1,475,863.59/1,370.12
6. Step 6: Final answer
   x = 1,077.18