Question 1 of 5
A city planner designs two straight walking paths that intersect at a point. One of the angles formed by the paths measures . A third path is built so that it is perpendicular to one of the original paths and lies inside the obtuse angle formed by the original two paths. What is the measure of the angle between the third path and the other original path?
Explanation
When two lines intersect, adjacent angles are supplementary. So if one angle is , the obtuse angle next to it is . The third path is perpendicular to one of the original paths, so it makes a angle with that path. Since this third path lies inside the angle, it splits that angle into two parts: and the angle we want. Therefore, the unknown angle is . The correct answer is .
Concept summary
Intersecting lines create vertical angles and supplementary adjacent angles, and a perpendicular line forms a angle that can split a larger angle into smaller parts.