Question

How to make a ${80}^{\circ }$ angle using compass and scale

Answer 1

From the school point, since, ${80}^{\circ }$ is not a multiple of $15$, the angle cannot be constructed.

But, from the engineering point, the angle can be constructed.

Steps of Construction:

(i) Let $A$ be a point on the a line.

(ii) With appropriate radius, draw a semi circle $BC$.

(iii) Now, with same radius and centre at $A$, cut an arc at point $D$.

(iv) Now, with $B$ and $D$ as centres and radius equal to $BD$, cut two arcs intersecting at point $E$.

(v) $\angle EAD={80}^{\circ }$