It looks like they are confused about how to convert from the entire circumference to a portion of it and decided to try dividing by 60. This student also needs a discussion around the meaning of that equals sign, because step 2 is not equal to step 3, and I’m sure they know that.

That’s a pet peeve of mine, I hate when kids add in operations mid-solving but say its still the equal.

I’m working with my colleagues in the elementary school to define = as equality, rather than “the next step in a calculation.” I’m hoping it pays off in a few years when their students get to high school.

This looks like a problem my precalc students are having as well. There is a deep lack of understanding about the relationship between angle measure and radian measure AND there is a reliance on formulas to get them through. I’d have a conversation pointing out what David said above and I’d have a conversation about similarity relationships. It can be seen as a part of a whole relationship regardless of the unit used to measure the angle.

It looks like the dreaded “take the numbers in the problem and see which operation sounds closest to making sense” approach. Maybe having them draw a diagram would help?

## 5 replies on “Arc Length”

It looks like they are confused about how to convert from the entire circumference to a portion of it and decided to try dividing by 60. This student also needs a discussion around the meaning of that equals sign, because step 2 is not equal to step 3, and I’m sure they know that.

That’s a pet peeve of mine, I hate when kids add in operations mid-solving but say its still the equal.

I’m working with my colleagues in the elementary school to define = as equality, rather than “the next step in a calculation.” I’m hoping it pays off in a few years when their students get to high school.

This looks like a problem my precalc students are having as well. There is a deep lack of understanding about the relationship between angle measure and radian measure AND there is a reliance on formulas to get them through. I’d have a conversation pointing out what David said above and I’d have a conversation about similarity relationships. It can be seen as a part of a whole relationship regardless of the unit used to measure the angle.

It looks like the dreaded “take the numbers in the problem and see which operation sounds closest to making sense” approach. Maybe having them draw a diagram would help?