I’m A Triangle, The Sum Of Any Two Side Lenghts,

Finish The Sentence

The sum of the measures of the triangles are known to be always equal to 180 degrees. In this item, we are given that angle J is equal to 72 degrees, angle K is equal to 36 degrees. If we let mK be the measure of the angle then, we can express the sum as,
     
180 = 72 + 36 + mK

The value of mK from the equation is 72 degrees. Since this is equal to J then, it is also a base angle. 

Then, the answer to the question is the second choice.