Finding the Third Proportional to 431.72 and 611.86

Step by Step Solution

1. Step 1: Write the proportion equation
   431.72 : 611.86 = 611.86 : x
2. Step 2: Convert to fraction form
   431.72/611.86 = 611.86/x
3. Step 3: Cross multiply
   431.72x = 611.86 × 611.86
4. Step 4: Simplify right side
   431.72x = 374,371.89
5. Step 5: Solve for x
   x = 374,371.89/431.72
6. Step 6: Final answer
   x = 867.17