PROGRAMMING:Finding the area of trapezoid
Input the top, bottom and height of a trapezoid from the keyboard, calculate the area of the trapezoid and output the result.
Input format: input the top, bottom and height of trapezoid, separated by commas.
Output format: area = trapezoidal area, printf ("area =%. 1F / N", area) can be used; Output.
###Input example:
3,5,6
3.2,4.6,2
```in
```
###Output example:
The corresponding output is given here. For example:
```out
area=24.0
area=7.8
```
answer：If there is no answer, please comment
Input format: input the top, bottom and height of trapezoid, separated by commas.
Output format: area = trapezoidal area, printf ("area =%. 1F / N", area) can be used; Output.
###Input example:
3,5,6
3.2,4.6,2
```in
```
###Output example:
The corresponding output is given here. For example:
```out
area=24.0
area=7.8
```
answer：If there is no answer, please comment