Finding the Third Proportional to 428.56 and 591.25

Step by Step Solution

1. Step 1: Write the proportion equation
   428.56 : 591.25 = 591.25 : x
2. Step 2: Convert to fraction form
   428.56/591.25 = 591.25/x
3. Step 3: Cross multiply
   428.56x = 591.25 × 591.25
4. Step 4: Simplify right side
   428.56x = 349,576.56
5. Step 5: Solve for x
   x = 349,576.56/428.56
6. Step 6: Final answer
   x = 815.70