Types of Triangles

Today we learned about different types of triangles - right, acute, and obtuse. We discussed that all triangles have two acute angles. The third angle is what determines its type. If the third angle is also acute, it's an acute triangle. If the third angle is right, it's a right triangle. If the third angle is obtuse, it's an obtuse triangle.

Naming and Measuring Angles

We began the week naming angles. Most of the students were familiar with the types of angles, but we reviewed the important characteristics of straight angles, obtuse angles, acute angles, and right angles.

Next we worked on measuring angles. Measurement is still a very abstract idea for 4th graders, so we began by discussing measurement as a whole. What do we use different measurement tools to measure? I posed the question, "Would a ruler work when trying to measure angles?" In the beginning of our discussion, many kids believed it would. After trying it out, they came to the conclusion that we needed something that measures in degrees. They understood the unit wasn't correct, but weren't sure what degrees actually are, though we had discussed degrees when classifying angles as right, acute, obtuse, and straight.

We went back to everything we already know about angles. Going in a complete circle means we have gone 360 degrees, while only going halfway around means we have gone 180 degrees. We already know that a right angle is 90 degrees. We already know a straight angle is 180 degrees. We know an acute angle measures between 1 degree and 89 degrees. We know an obtuse angle measures between 91 and 179 degrees. Once we illustrated that, we decided we could half each 90 degree piece and figure out where 45 degrees and 135 degrees are located. Next we moved to

Right Angles

As we begin to explore right angles, we first discuss the degrees involved. From our prior knowledge regarding quadrilaterals, we know they are made up of 360 degrees. We further the discussion by looking at a quadrilateral that is made up of four right angles. If there are four, and they're all equal, they must measure 90 degrees.

After this discussion, we decide how we might find right angles within a shape. This leads us to using the edge of an index card. I find this helps those kiddos who struggle a bit more with spatial concepts.

After lots of playing around with shapes and labeling their angles, we move on to combining polygons to make right angles. This is a bit more challenging. This always leads to great discussion about what size angles might we pick when trying to make a right angles. The kids can see they need to be looking for angles smaller than 90 degrees, otherwise their angles are going to be too large. As the kids found angle combinations that worked, they recorded them in their journals.

Math Review Folder

Outside Geometry Review

Today we finished our math review folder! We've been working on this a little each day for about 2 weeks. The folder contains some brief reminders and tips for all our big concepts from the year. We like to spend a couple of weeks before our STAAR test reviewing the year's concepts. As we reviewed a concept, we added a brief entry into our folder.

Geometry Review

Inside View

Area, Perimeter, Volume Review

Measurement Review

Lines and Angles Review

Measurement Conversion Review

Place Value Chart - Closed

Place Value Chart - Open

Fractions and Decimals Review

Angles Search

Today the kids went on an angle search around the school. They paired up and used iPads to take two pictures of acute angles, two pictures of obtuse angles, and two pictures of right angles. Here are just a few of our pictures.

After finding the pictures, the students used the app Educreations to create a movie slide show with narration telling about each angle. For example, when an acute angle is pictured, the kids can be heard saying, "This is our example of an acute angle. Acute angles can measure from 1 degree to 89 degrees. We estimate this angle to be about 45 degrees."