It is going to be A hope this helps
The set of numbers running from least to greatest is C.
An isosceles triangle has two identical angles.
The three angles need to add up to 180 degrees.
If one angle is 100 then the other two angles added together need to equal 180-100 =‘80 degrees.
Since two angles need to be the same the other angles are 80 / 2 = 40 degrees each.
The answer is 40
