Finding the Third Proportional to 142,278 and 309,612

Step by Step Solution

1. Step 1: Write the proportion equation
   142,278 : 309,612 = 309,612 : x
2. Step 2: Convert to fraction form
   142,278/309,612 = 309,612/x
3. Step 3: Cross multiply
   142,278x = 309,612 × 309,612
4. Step 4: Simplify right side
   142,278x = 95,859,590,544
5. Step 5: Solve for x
   x = 95,859,590,544/142,278
6. Step 6: Final answer
   x = 673,748.51