Finding the Third Proportional to 285.56 and 429.69

Step by Step Solution

1. Step 1: Write the proportion equation
   285.56 : 429.69 = 429.69 : x
2. Step 2: Convert to fraction form
   285.56/429.69 = 429.69/x
3. Step 3: Cross multiply
   285.56x = 429.69 × 429.69
4. Step 4: Simplify right side
   285.56x = 184,631.35
5. Step 5: Solve for x
   x = 184,631.35/285.56
6. Step 6: Final answer
   x = 646.55