Finding the Fourth Proportional to 2,211.82, 3,316.20 and 978.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,211.82 : 3,316.20 = 978.56 : x
2. Step 2: Convert to fraction form
   2,211.82/3,316.20 = 978.56/x
3. Step 3: Cross multiply
   2,211.82x = 3,316.20 × 978.56
4. Step 4: Simplify right side
   2,211.82x = 3,245,111.51
5. Step 5: Solve for x
   x = 3,245,111.51/2,211.82
6. Step 6: Final answer
   x = 1,467.17