Finding the Fourth Proportional to 139,036.77, 191,871.45 and 78,613.20

Step by Step Solution

1. Step 1: Write the proportion equation
   139,036.77 : 191,871.45 = 78,613.20 : x
2. Step 2: Convert to fraction form
   139,036.77/191,871.45 = 78,613.20/x
3. Step 3: Cross multiply
   139,036.77x = 191,871.45 × 78,613.20
4. Step 4: Simplify right side
   139,036.77x = 15,083,628,673.14
5. Step 5: Solve for x
   x = 15,083,628,673.14/139,036.77
6. Step 6: Final answer
   x = 108,486.62