Finding the Third Proportional to 357.50 and 420.50

Step by Step Solution

1. Step 1: Write the proportion equation
   357.50 : 420.50 = 420.50 : x
2. Step 2: Convert to fraction form
   357.50/420.50 = 420.50/x
3. Step 3: Cross multiply
   357.50x = 420.50 × 420.50
4. Step 4: Simplify right side
   357.50x = 176,820.25
5. Step 5: Solve for x
   x = 176,820.25/357.50
6. Step 6: Final answer
   x = 494.60