How many sides does a regular polygon have if one exterior angle is 90 degrees? 3 4 5 6?

4 sides

B is correct

Step-by-step explanation:

A regular polygon has each exterior angle is equal.

The sum of all angle of exterior angles of regular polygon is 360°

For given regular polygon each exterior angle is 90°

Let use n number of side of polygon or n exterior angles.

Total sum of exterior angles = 90n

It must be equal to 360° because sum of all exterior angles.

90n = 360°

    n = 4

Hence, The number of sides of regular polygon whose each exterior angle 90° is 4

this answer is !