Finding the Fourth Proportional to 97.72, 145.72 and 90.88

Step by Step Solution

1. Step 1: Write the proportion equation
   97.72 : 145.72 = 90.88 : x
2. Step 2: Convert to fraction form
   97.72/145.72 = 90.88/x
3. Step 3: Cross multiply
   97.72x = 145.72 × 90.88
4. Step 4: Simplify right side
   97.72x = 13,243.03
5. Step 5: Solve for x
   x = 13,243.03/97.72
6. Step 6: Final answer
   x = 135.52