Finding the Fourth Proportional to 99.50, 149.63 and 78.98

Step by Step Solution

1. Step 1: Write the proportion equation
   99.50 : 149.63 = 78.98 : x
2. Step 2: Convert to fraction form
   99.50/149.63 = 78.98/x
3. Step 3: Cross multiply
   99.50x = 149.63 × 78.98
4. Step 4: Simplify right side
   99.50x = 11,816.63
5. Step 5: Solve for x
   x = 11,816.63/99.50
6. Step 6: Final answer
   x = 118.77