Quick! [0, infty) open or closed interval?

True or false? a triangle can be circumscribed about a given circle

Julia is going for a walk through the neighborhood. what unit of measure is most appropriate to describe the distance she walks?

Astick 2 m long is placed vertically at point b. the top of the stick is in line with the top of a tree as seen from point a, which is 3 m from the stick and 30 m from the tree. how tall is the tree?