Finding the Third Proportional to 428.63 and 648.56

Step by Step Solution

1. Step 1: Write the proportion equation
   428.63 : 648.56 = 648.56 : x
2. Step 2: Convert to fraction form
   428.63/648.56 = 648.56/x
3. Step 3: Cross multiply
   428.63x = 648.56 × 648.56
4. Step 4: Simplify right side
   428.63x = 420,633.32
5. Step 5: Solve for x
   x = 420,633.32/428.63
6. Step 6: Final answer
   x = 981.36