Finding the Fourth Proportional to 83.72, 115.59 and 63.05

Step by Step Solution

1. Step 1: Write the proportion equation
   83.72 : 115.59 = 63.05 : x
2. Step 2: Convert to fraction form
   83.72/115.59 = 63.05/x
3. Step 3: Cross multiply
   83.72x = 115.59 × 63.05
4. Step 4: Simplify right side
   83.72x = 7,287.37
5. Step 5: Solve for x
   x = 7,287.37/83.72
6. Step 6: Final answer
   x = 87.05