Finding the Third Proportional to 399.94 and 872.72

Step by Step Solution

1. Step 1: Write the proportion equation
   399.94 : 872.72 = 872.72 : x
2. Step 2: Convert to fraction form
   399.94/872.72 = 872.72/x
3. Step 3: Cross multiply
   399.94x = 872.72 × 872.72
4. Step 4: Simplify right side
   399.94x = 761,638.02
5. Step 5: Solve for x
   x = 761,638.02/399.94
6. Step 6: Final answer
   x = 1,904.39