Finding the Fourth Proportional to 1,100.79, 1,642.68 and 978.08

Step by Step Solution

1. Step 1: Write the proportion equation
   1,100.79 : 1,642.68 = 978.08 : x
2. Step 2: Convert to fraction form
   1,100.79/1,642.68 = 978.08/x
3. Step 3: Cross multiply
   1,100.79x = 1,642.68 × 978.08
4. Step 4: Simplify right side
   1,100.79x = 1,606,664.24
5. Step 5: Solve for x
   x = 1,606,664.24/1,100.79
6. Step 6: Final answer
   x = 1,459.56