Finding the Fourth Proportional to 98.32, 135.55 and 78.72

Step by Step Solution

1. Step 1: Write the proportion equation
   98.32 : 135.55 = 78.72 : x
2. Step 2: Convert to fraction form
   98.32/135.55 = 78.72/x
3. Step 3: Cross multiply
   98.32x = 135.55 × 78.72
4. Step 4: Simplify right side
   98.32x = 10,670.50
5. Step 5: Solve for x
   x = 10,670.50/98.32
6. Step 6: Final answer
   x = 108.53