Finding the Fourth Proportional to 156.31, 215.76 and 109.69

Step by Step Solution

1. Step 1: Write the proportion equation
   156.31 : 215.76 = 109.69 : x
2. Step 2: Convert to fraction form
   156.31/215.76 = 109.69/x
3. Step 3: Cross multiply
   156.31x = 215.76 × 109.69
4. Step 4: Simplify right side
   156.31x = 23,666.59
5. Step 5: Solve for x
   x = 23,666.59/156.31
6. Step 6: Final answer
   x = 151.40