Finding the Fourth Proportional to 82.16, 123.72 and 70.12

Step by Step Solution

1. Step 1: Write the proportion equation
   82.16 : 123.72 = 70.12 : x
2. Step 2: Convert to fraction form
   82.16/123.72 = 70.12/x
3. Step 3: Cross multiply
   82.16x = 123.72 × 70.12
4. Step 4: Simplify right side
   82.16x = 8,675.25
5. Step 5: Solve for x
   x = 8,675.25/82.16
6. Step 6: Final answer
   x = 105.59