Finding the Fourth Proportional to 78,390.10, 117,736.35 and 67,170.79

Step by Step Solution

1. Step 1: Write the proportion equation
   78,390.10 : 117,736.35 = 67,170.79 : x
2. Step 2: Convert to fraction form
   78,390.10/117,736.35 = 67,170.79/x
3. Step 3: Cross multiply
   78,390.10x = 117,736.35 × 67,170.79
4. Step 4: Simplify right side
   78,390.10x = 7,908,443,641.22
5. Step 5: Solve for x
   x = 7,908,443,641.22/78,390.10
6. Step 6: Final answer
   x = 100,885.75