In a polygon, the sum of the measures of the exterior angles — one at each vertex — is 360^(∘).
This means that the sum of the exterior angles of a regular pentagon is also 360^(∘). A pentagon has 5 vertices and 5 exterior angles.
In a regular polygon, all exterior angles are congruent. Therefore, a regular pentagon has 5 congruent exterior angles. To find the measure of one of them, we will divide 360^(∘) by 5.
360/5 = 72^(∘)
