Finding the Fourth Proportional to 6,662.03, 9,991.31 and 1,980.78

Step by Step Solution

1. Step 1: Write the proportion equation
   6,662.03 : 9,991.31 = 1,980.78 : x
2. Step 2: Convert to fraction form
   6,662.03/9,991.31 = 1,980.78/x
3. Step 3: Cross multiply
   6,662.03x = 9,991.31 × 1,980.78
4. Step 4: Simplify right side
   6,662.03x = 19,790,587.37
5. Step 5: Solve for x
   x = 19,790,587.37/6,662.03
6. Step 6: Final answer
   x = 2,970.65