Finding the Fourth Proportional to 105.47, 145.21 and 100.34

Step by Step Solution

1. Step 1: Write the proportion equation
   105.47 : 145.21 = 100.34 : x
2. Step 2: Convert to fraction form
   105.47/145.21 = 100.34/x
3. Step 3: Cross multiply
   105.47x = 145.21 × 100.34
4. Step 4: Simplify right side
   105.47x = 14,570.37
5. Step 5: Solve for x
   x = 14,570.37/105.47
6. Step 6: Final answer
   x = 138.15