Finding the Fourth Proportional to 379.35, 522.72 and 309.15

Step by Step Solution

1. Step 1: Write the proportion equation
   379.35 : 522.72 = 309.15 : x
2. Step 2: Convert to fraction form
   379.35/522.72 = 309.15/x
3. Step 3: Cross multiply
   379.35x = 522.72 × 309.15
4. Step 4: Simplify right side
   379.35x = 161,598.89
5. Step 5: Solve for x
   x = 161,598.89/379.35
6. Step 6: Final answer
   x = 425.99