Finding the Fourth Proportional to 76,791.72, 105,978.74 and 42,811.21

Step by Step Solution

1. Step 1: Write the proportion equation
   76,791.72 : 105,978.74 = 42,811.21 : x
2. Step 2: Convert to fraction form
   76,791.72/105,978.74 = 42,811.21/x
3. Step 3: Cross multiply
   76,791.72x = 105,978.74 × 42,811.21
4. Step 4: Simplify right side
   76,791.72x = 4,537,077,614.67
5. Step 5: Solve for x
   x = 4,537,077,614.67/76,791.72
6. Step 6: Final answer
   x = 59,082.90