Finding the Fourth Proportional to 91.82, 137.93 and 78.45

Step by Step Solution

1. Step 1: Write the proportion equation
   91.82 : 137.93 = 78.45 : x
2. Step 2: Convert to fraction form
   91.82/137.93 = 78.45/x
3. Step 3: Cross multiply
   91.82x = 137.93 × 78.45
4. Step 4: Simplify right side
   91.82x = 10,820.22
5. Step 5: Solve for x
   x = 10,820.22/91.82
6. Step 6: Final answer
   x = 117.85