Finding the Fourth Proportional to 309,768.64, 427,611.72 and 209,302.72

Step by Step Solution

1. Step 1: Write the proportion equation
   309,768.64 : 427,611.72 = 209,302.72 : x
2. Step 2: Convert to fraction form
   309,768.64/427,611.72 = 209,302.72/x
3. Step 3: Cross multiply
   309,768.64x = 427,611.72 × 209,302.72
4. Step 4: Simplify right side
   309,768.64x = 89,500,296,099.88
5. Step 5: Solve for x
   x = 89,500,296,099.88/309,768.64
6. Step 6: Final answer
   x = 288,926.26