Finding the Fourth Proportional to 156.30, 215.72 and 90.82

Step by Step Solution

1. Step 1: Write the proportion equation
   156.30 : 215.72 = 90.82 : x
2. Step 2: Convert to fraction form
   156.30/215.72 = 90.82/x
3. Step 3: Cross multiply
   156.30x = 215.72 × 90.82
4. Step 4: Simplify right side
   156.30x = 19,591.69
5. Step 5: Solve for x
   x = 19,591.69/156.30
6. Step 6: Final answer
   x = 125.35