This triangle is an isosceles triangle (as indicated by the tick marks through the two sides). The base angles of isosceles triangles are congruent; this means the measure of angle x is congruent to the measure of the unlabeled interior angle.
The sum of the interior angles of all triangles is 180 degrees; you can find x by setting the sum of the two unknown angles, x, and 98 equal to 180 and solving algebraically.
180 = 98 + x + x
180 = 98 + 2x
82 = 2x
41 = x
Answer:
x = 41