Finding the Radius From a Given Circumference or Area
Lesson 10 of 37
Objective: SWBAT find the radius or diameter of a circle given its circumference or area
I would like students to solve these problems using the teacher model. However, GP5 provides a chance for us to discuss the structure of the measurements (MP7). As students explain their thinking here they have a chance to attend to precision (MP6) as they are careful to distinguish between the value being a square of the radius or representing the diameter.
I will ask students to represent the problems in an equation, even if they see the shortcut, however, they do not have to follow the steps. A brief explanation of how they know the radius and diameter is sufficient (MP3). Students then have 4 extension problems where 3.14 was used for PI. Now it is not as easy to “eyeball” the radius or diameter so it is a bit more helpful to model the problem using the formula (MP4).
The exit ticket is in multiple choice format. I have chosen distracter answer choices that reflect common errors when working with radius, diameter, and square roots.