Monday I asked my students to determine whether this triangle was equilateral, isosceles, or scalene, and to prove their answer. The hint is in the post title: this is a Pythagorean Theorem activity. Here is the original triangle: If you said
Pythagorean Theorem Follow-Up
Activity for the big kids today: Without using a ruler, determine whether this triangle is equilateral, isosceles, or scalene. Prove it.
Pythagorean Theorem
In over our heads with radicals in 8th grade Algebra this week, so we took some time to review the Pythagorean Theorem. Â Geometry is so beautifully concrete. Â In addition to demonstrations you can do with drawings and such, here’s an
Geometry in the Real World
Whenever I’m working on geometry with my students, I try to keep the focus as real-world as possible. So much of math operates in the abstract; geometry, by contrast, is thoroughly tangible. This is a time when we can easily
Geometry Across the Curriculum
I use geometric drawing across the curriculum in several projects. Below is an in-progress shot of an 8th-grader’s design for a stained glass window, an assignment from my medieval history unit that incorporates symbolism along with geometric design. In world
Construct a Hexagon
The construction for a regular hexagon is a favorite of my students every year and the one most of them choose as a basis for their geometric design project. We are simply going to begin with a line and use
Construct a Square
This simple, elegant construction yields a square simply by using the steps to bisect a segment. Begin by using your compass to draw a circle, making sure to mark its center. With your straight edge, draw the diameter of the
Bisect an Angle
Today we’ll be bisecting an angle, i.e. cutting an angle in half without using a protractor to measure. Â Begin with any angle and draw an arc from the vertex (V) such that your arc crosses both rays of the angle.
Bisect a Segment
Today we’ll be doing a very simple construction — bisecting a segment. Â In other words, we will be cutting a line segment in half. Â Begin by drawing matching circles from your two endpoints (A and B). Â The radius of the
Identify Geometric Shapes
Here’s a little activity to wrap up our geometry study for the week. Â Have your students consider the following drawing and try to identify as many polygons as they can. Â If they need a little guidance, here are some possibilities…