Finding the Fourth Proportional to 2,953.20, 4,428.60 and 978.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,953.20 : 4,428.60 = 978.72 : x
2. Step 2: Convert to fraction form
   2,953.20/4,428.60 = 978.72/x
3. Step 3: Cross multiply
   2,953.20x = 4,428.60 × 978.72
4. Step 4: Simplify right side
   2,953.20x = 4,334,359.39
5. Step 5: Solve for x
   x = 4,334,359.39/2,953.20
6. Step 6: Final answer
   x = 1,467.68