Finding the Fourth Proportional to 91.69, 136.77 and 78.01

Step by Step Solution

1. Step 1: Write the proportion equation
   91.69 : 136.77 = 78.01 : x
2. Step 2: Convert to fraction form
   91.69/136.77 = 78.01/x
3. Step 3: Cross multiply
   91.69x = 136.77 × 78.01
4. Step 4: Simplify right side
   91.69x = 10,669.38
5. Step 5: Solve for x
   x = 10,669.38/91.69
6. Step 6: Final answer
   x = 116.36