Finding the Fourth Proportional to 1,567.60, 2,162.64 and 978.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,567.60 : 2,162.64 = 978.88 : x
2. Step 2: Convert to fraction form
   1,567.60/2,162.64 = 978.88/x
3. Step 3: Cross multiply
   1,567.60x = 2,162.64 × 978.88
4. Step 4: Simplify right side
   1,567.60x = 2,116,965.04
5. Step 5: Solve for x
   x = 2,116,965.04/1,567.60
6. Step 6: Final answer
   x = 1,350.45