Finding the Fourth Proportional to 1,315.88, 1,969.72 and 969.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.88 : 1,969.72 = 969.60 : x
2. Step 2: Convert to fraction form
   1,315.88/1,969.72 = 969.60/x
3. Step 3: Cross multiply
   1,315.88x = 1,969.72 × 969.60
4. Step 4: Simplify right side
   1,315.88x = 1,909,845.47
5. Step 5: Solve for x
   x = 1,909,845.47/1,315.88
6. Step 6: Final answer
   x = 1,451.38