Finding the Fourth Proportional to 156.09, 215.34 and 100.82

Step by Step Solution

1. Step 1: Write the proportion equation
   156.09 : 215.34 = 100.82 : x
2. Step 2: Convert to fraction form
   156.09/215.34 = 100.82/x
3. Step 3: Cross multiply
   156.09x = 215.34 × 100.82
4. Step 4: Simplify right side
   156.09x = 21,710.58
5. Step 5: Solve for x
   x = 21,710.58/156.09
6. Step 6: Final answer
   x = 139.09