Finding the Third Proportional to 310.39 and 674.89

Step by Step Solution

1. Step 1: Write the proportion equation
   310.39 : 674.89 = 674.89 : x
2. Step 2: Convert to fraction form
   310.39/674.89 = 674.89/x
3. Step 3: Cross multiply
   310.39x = 674.89 × 674.89
4. Step 4: Simplify right side
   310.39x = 455,482.63
5. Step 5: Solve for x
   x = 455,482.63/310.39
6. Step 6: Final answer
   x = 1,467.43