Finding the Third Proportional to 278.63 and 429.38

Step by Step Solution

1. Step 1: Write the proportion equation
   278.63 : 429.38 = 429.38 : x
2. Step 2: Convert to fraction form
   278.63/429.38 = 429.38/x
3. Step 3: Cross multiply
   278.63x = 429.38 × 429.38
4. Step 4: Simplify right side
   278.63x = 184,362.89
5. Step 5: Solve for x
   x = 184,362.89/278.63
6. Step 6: Final answer
   x = 661.69