Answer:
The length of the actual pen=14 meters.
Explanation:
Given The scale of the drawing was 1 millimetre : 7 metres. It means that for every millimetre of the drawing the actual length is 7 metres.
let the actual length of the goat pen be x
![1 mm--->7m](https://img.qammunity.org/2020/formulas/mathematics/high-school/izvj3a88c66vc1gpz9roxuaic06ixkjbn0.png)
![2mm--->xm](https://img.qammunity.org/2020/formulas/mathematics/high-school/yhj1ge9lb3ru8nav9u35ckflgcw01h34py.png)
on cross multiplication we get
![x*1=7*2](https://img.qammunity.org/2020/formulas/mathematics/high-school/xqymkaxx47fgar99j5uyblsy0e7y5rf7ur.png)
![x=14](https://img.qammunity.org/2020/formulas/mathematics/middle-school/46129xhthd1isp1am8t6gofjkv26osuovh.png)