Finding the Third Proportional to 459.42 and 643.57

Step by Step Solution

1. Step 1: Write the proportion equation
   459.42 : 643.57 = 643.57 : x
2. Step 2: Convert to fraction form
   459.42/643.57 = 643.57/x
3. Step 3: Cross multiply
   459.42x = 643.57 × 643.57
4. Step 4: Simplify right side
   459.42x = 414,182.75
5. Step 5: Solve for x
   x = 414,182.75/459.42
6. Step 6: Final answer
   x = 901.53