Finding the Fourth Proportional to 11.50, 15.86 and 10.05

Step by Step Solution

1. Step 1: Write the proportion equation
   11.50 : 15.86 = 10.05 : x
2. Step 2: Convert to fraction form
   11.50/15.86 = 10.05/x
3. Step 3: Cross multiply
   11.50x = 15.86 × 10.05
4. Step 4: Simplify right side
   11.50x = 159.39
5. Step 5: Solve for x
   x = 159.39/11.50
6. Step 6: Final answer
   x = 13.86