How many feet of lights should I buy for my tree?

Check out our Christmas Tree! We need to buy lights for the tree.  Without calculating, guess how many feet of lights we will need. What information would help you to better estimate that length? (Give students time to consider what info they have and what they need). Here is a picture of the tree with its measurements.

The tree is in the shape of a cone. Students might find knowing the surface area of a cone helpful.  Here is a video on finding surface and lateral area of a cone.  Note: Students will need to know the slant height of the tree. Students that are comfortable with the Pythagorean Theorem can find this. Otherwise, you might give students the slant height of ten feet. Watch the video to find out how many feet of lights we used to decorate this tree.

For Adventurer members we have an editable Word doc of this activity and a solution with teacher guide below.