Finding the Fourth Proportional to 1,978.64, 2,969.16 and 1,113.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.64 : 2,969.16 = 1,113.20 : x
2. Step 2: Convert to fraction form
   1,978.64/2,969.16 = 1,113.20/x
3. Step 3: Cross multiply
   1,978.64x = 2,969.16 × 1,113.20
4. Step 4: Simplify right side
   1,978.64x = 3,305,268.91
5. Step 5: Solve for x
   x = 3,305,268.91/1,978.64
6. Step 6: Final answer
   x = 1,670.48