Finding the Fourth Proportional to 90.76, 136.25 and 78.00

Step by Step Solution

1. Step 1: Write the proportion equation
   90.76 : 136.25 = 78.00 : x
2. Step 2: Convert to fraction form
   90.76/136.25 = 78.00/x
3. Step 3: Cross multiply
   90.76x = 136.25 × 78.00
4. Step 4: Simplify right side
   90.76x = 10,626.43
5. Step 5: Solve for x
   x = 10,626.43/90.76
6. Step 6: Final answer
   x = 117.09