Finding the Fourth Proportional to 1,223.48, 1,688.78 and 976.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.48 : 1,688.78 = 976.50 : x
2. Step 2: Convert to fraction form
   1,223.48/1,688.78 = 976.50/x
3. Step 3: Cross multiply
   1,223.48x = 1,688.78 × 976.50
4. Step 4: Simplify right side
   1,223.48x = 1,649,093.67
5. Step 5: Solve for x
   x = 1,649,093.67/1,223.48
6. Step 6: Final answer
   x = 1,347.87