Which one of the following angles cannot be constructed using a compass and ruler?
The correct option is D: 100∘
We can draw 60∘ and bisect it to get 30∘.
Similarly, we can bisect 30∘ and get 15∘.
Also, we can draw 90∘ and bisect it to get 45∘.
But, 100∘ cannot be drawn using compass and ruler.
Using compass and ruler, we can only draw angles which are multiples of 15 and also the angles which can be obtained by bisecting it.