Finding the Fourth Proportional to 91,300.80, 136,965.92 and 28,120.91

Step by Step Solution

1. Step 1: Write the proportion equation
   91,300.80 : 136,965.92 = 28,120.91 : x
2. Step 2: Convert to fraction form
   91,300.80/136,965.92 = 28,120.91/x
3. Step 3: Cross multiply
   91,300.80x = 136,965.92 × 28,120.91
4. Step 4: Simplify right side
   91,300.80x = 3,851,605,483.95
5. Step 5: Solve for x
   x = 3,851,605,483.95/91,300.80
6. Step 6: Final answer
   x = 42,185.89