Finding the Fourth Proportional to 1,275.45, 1,760.18 and 715.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,275.45 : 1,760.18 = 715.91 : x
2. Step 2: Convert to fraction form
   1,275.45/1,760.18 = 715.91/x
3. Step 3: Cross multiply
   1,275.45x = 1,760.18 × 715.91
4. Step 4: Simplify right side
   1,275.45x = 1,260,136.96
5. Step 5: Solve for x
   x = 1,260,136.96/1,275.45
6. Step 6: Final answer
   x = 987.99