Finding the Fourth Proportional to 770.69, 1,156.17 and 338.15

Step by Step Solution

1. Step 1: Write the proportion equation
   770.69 : 1,156.17 = 338.15 : x
2. Step 2: Convert to fraction form
   770.69/1,156.17 = 338.15/x
3. Step 3: Cross multiply
   770.69x = 1,156.17 × 338.15
4. Step 4: Simplify right side
   770.69x = 390,958.89
5. Step 5: Solve for x
   x = 390,958.89/770.69
6. Step 6: Final answer
   x = 507.28