Finding the Fourth Proportional to 428,878.42, 642,505.57 and 286,293.72

Step by Step Solution

1. Step 1: Write the proportion equation
   428,878.42 : 642,505.57 = 286,293.72 : x
2. Step 2: Convert to fraction form
   428,878.42/642,505.57 = 286,293.72/x
3. Step 3: Cross multiply
   428,878.42x = 642,505.57 × 286,293.72
4. Step 4: Simplify right side
   428,878.42x = 183,945,309,756.02
5. Step 5: Solve for x
   x = 183,945,309,756.02/428,878.42
6. Step 6: Final answer
   x = 428,898.50