Question

Which of the following angles can be trisected using only a compass and straightedge?

A.90
B.80
C.70
D.100

Answer 1

I believe it's A......

Answer 2

The correct option is (A) 90°

Explanation:

The angles can be trisected which constructive angle θ, an angle of measure 3θ can be trivially trisected.

So, the angle in option (A) is written as 3θ.

3θ=3(30°)

but rest options can't write as 3θ.

Hence, the correct option is (A) 90°