Finding the Fourth Proportional to 948.72, 1,308.78 and 817.50

Step by Step Solution

1. Step 1: Write the proportion equation
   948.72 : 1,308.78 = 817.50 : x
2. Step 2: Convert to fraction form
   948.72/1,308.78 = 817.50/x
3. Step 3: Cross multiply
   948.72x = 1,308.78 × 817.50
4. Step 4: Simplify right side
   948.72x = 1,069,927.65
5. Step 5: Solve for x
   x = 1,069,927.65/948.72
6. Step 6: Final answer
   x = 1,127.76