Finding the Fourth Proportional to 915.57, 1,263.72 and 767.97

Step by Step Solution

1. Step 1: Write the proportion equation
   915.57 : 1,263.72 = 767.97 : x
2. Step 2: Convert to fraction form
   915.57/1,263.72 = 767.97/x
3. Step 3: Cross multiply
   915.57x = 1,263.72 × 767.97
4. Step 4: Simplify right side
   915.57x = 970,499.05
5. Step 5: Solve for x
   x = 970,499.05/915.57
6. Step 6: Final answer
   x = 1,059.99