Finding the Fourth Proportional to 1,315.58, 1,969.72 and 663.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.58 : 1,969.72 = 663.12 : x
2. Step 2: Convert to fraction form
   1,315.58/1,969.72 = 663.12/x
3. Step 3: Cross multiply
   1,315.58x = 1,969.72 × 663.12
4. Step 4: Simplify right side
   1,315.58x = 1,306,159.07
5. Step 5: Solve for x
   x = 1,306,159.07/1,315.58
6. Step 6: Final answer
   x = 992.84