The value of s is equal to 40°
The two triangles under the same line are congruent given that they are formed by similar pairs of parallel lines which implies that the interior angles r and s are equal. Thus r = s.
Angle t is equal to 100° as it is a corresponding angle to the vertical angle opposite 100°. so;
100° + r + s = 180° {sum of interior angles of a triangle}
100° + 2s = 180° {since r = s}
2s = 180 - 100 {collect like terms}
2s = 80
s = 80/2 {divide through by 2}
s = 40°
Therefore, the measure of the interior angle s is derived to be equal to 40°.