Equilateral Triangle Inscribed in a Circle

Integrating Compasses

Compasses remain reliable and helpful tools to work with when teaching lessons that revolve around circles. Many figures can be drawn inside a circle with all their vertices touching the circle’s edge. Today, we are going to focus on inscribing the equilateral triangle.

An inscribed triangle is one that is drawn inside a circle. Some of the geometry terms that students will review in this lesson include circle, radius, arcs, and equilateral triangles.

This lesson is a chance to teach and reinforce the skill of using a compass. You can demonstrate for students how to measure the radius of a circle and draw arcs based on that measurement.

Connecting Activity

During this connecting activity you will find another good opportunity to let students interact in groups. It allows them to reinforce the lesson when they recall their thought process to get to the answer.

As they work through their practice problems, monitor and check on the different groups to see which students may need more guidance, maybe heading in the wrong direction, or are completely off topic as our student occasionally like to be.

Group Disussions

This activity allows for great discussions, especially if some groups show that they have a firmer grasp on the concept. As those groups wrap up, they can help another group who is struggling so that everyone remains engaged in the lesson.

After everyone is wrapping up their work,  review the main points of the lesson to clear up any misconceptions, and assess how well the students did.

Inscribing Equilateral Triangles within a Circle Lesson Plan

There is a free lesson plan for inscribing equilateral triangles into circles here. The activity for this lesson plan includes step by step instructions for leading students through a group activity with compasses.

Pick up this great resource which includes a lesson presentation, bellringer, activity with a worksheet, exit slip and more all aligned to the common core standards.

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