Finding the Fourth Proportional to 103.51, 142.79 and 86.10

Step by Step Solution

1. Step 1: Write the proportion equation
   103.51 : 142.79 = 86.10 : x
2. Step 2: Convert to fraction form
   103.51/142.79 = 86.10/x
3. Step 3: Cross multiply
   103.51x = 142.79 × 86.10
4. Step 4: Simplify right side
   103.51x = 12,294.22
5. Step 5: Solve for x
   x = 12,294.22/103.51
6. Step 6: Final answer
   x = 118.77