Finding the Fourth Proportional to 1,980.72, 2,971.35 and 1,278.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,980.72 : 2,971.35 = 1,278.48 : x
2. Step 2: Convert to fraction form
   1,980.72/2,971.35 = 1,278.48/x
3. Step 3: Cross multiply
   1,980.72x = 2,971.35 × 1,278.48
4. Step 4: Simplify right side
   1,980.72x = 3,798,822.69
5. Step 5: Solve for x
   x = 3,798,822.69/1,980.72
6. Step 6: Final answer
   x = 1,917.90