Question

With a ruler and a compass which of the following angles cannot be constructed?

• A. 80
• B. ${60}^{\circ }$
• C. ${45}^{\circ }$
• D. ${75}^{\circ }$

Answer 1

The correct option is A

80

With a ruler and a compass we can construct ${15}^{\circ }$, ${30}^{\circ }$, ${45}^{\circ }$, ${60}^{\circ }$, ${75}^{\circ }$, ${90}^{\circ }$, ${105}^{\circ }$ angles. We cannot construct a ${55}^{\circ }$. Generally, the angles that can be constructed are multiples of ${15}^{\circ }$.