Finding the Fourth Proportional to 109.16, 162.77 and 105.21

Step by Step Solution

1. Step 1: Write the proportion equation
   109.16 : 162.77 = 105.21 : x
2. Step 2: Convert to fraction form
   109.16/162.77 = 105.21/x
3. Step 3: Cross multiply
   109.16x = 162.77 × 105.21
4. Step 4: Simplify right side
   109.16x = 17,124.51
5. Step 5: Solve for x
   x = 17,124.51/109.16
6. Step 6: Final answer
   x = 156.88