During my internship I frequently used a tool called GeoGebra.
GeoGebra is an interactive tool where students can work on different topics such as Algebra, Geometry, Probability and Graphics. I specifically used the tool for measuring angles on parallel lines intersected by a transversals. I think this tool is good because it allows for hands-on work for students. There is so much that can be done with this site. It is also good for teachers who want to show an example in class. For example, if you were teaching a lesson on graphing trig functions you could construct that graph on GeoGebra and give the students a visual of what that function should look like. Another great aspect of this tool is there are materials available that show examples of a variety of topics.
My students had a lot of fun when working with GeoGebra, they were fully engaged and were able to complete the task I had set out for them. The only drawback of this tool is that it can be very finicky when measuring an angle and there is so much that this tool can do that it can be overwhelming for some students.
This tool can not replace direct instruction however there are cases where it would great with inquiry based instruction. In my class I had students measure angles to develop a stronger understanding of terms such as, co-interior angles, alternate exterior angles..etc., which fits directly into the Workplace and Apprenticeship 10 Curriculum. I believe this tool would work well with any math class, specifically in the higher grades.