Illustrative Mathematics
Joining Two Midpoints of Sides of a Triangle
Without ever using the actual term, this exercise has the learner develop the key properties of the midsegment of a triangle. This task leads the class to discover a proof of similar triangles using the properties of parallel...
Illustrative Mathematics
A Midpoint Miracle
Young geometers develop one of the fundamental properties of quadrilaterals (connecting side midpoints gives a parallelogram) in this short but thought-provoking exercise. Using a combination of hands-on techniques and abstract algebraic...
Illustrative Mathematics
Lines of Symmetry for Triangles
What can symmetry tell us about triangles? After looking at four examples, learners will come to realize that lines of symmetry are different for equilateral, isosceles, and scalene triangles. Use this guided practice activity as an...
Illustrative Mathematics
Midpoints of the Sides of a Paralellogram
This task asks learners to prove that the segment joining the midpoints of two sides of a parallelogram is both congruent and parallel to an adjacent side of the parallelogram. The activity would be good to use in a discussion about how...
Education Development Center
Proof with Parallelogram Vertices
Geometric figures are perfect to use for proofs. Scholars prove conjectures about whether given points lie on a triangle and about midpoints. They use a provided dialogue among fictional students to frame their responses.
Curated OER
Complex Distance
Have learners graph complex numbers to gain a visual and mathematical understanding of the distance and the midpoint between two complex numbers. This lesson is short, but to the point, and addresses an important complex number...
Curated OER
Reflections and Equilateral Triangles II
Given the lines of symmetry in an equilateral triangle, your learners find where the pre-image vertices are mapped onto the new image. They explore the properties of equilateral triangles, the impact of reflections, and the...
Illustrative Mathematics
Reflections and Isosceles Triangles
Geometers explore symmetries of isosceles triangles by using rigid transformations of the plane. They complete four tasks, including congruence proofs, which illustrate the relationship between congruence and rigid transformations. The...
Illustrative Mathematics
Tangent to a Circle From a Point
Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using...
Illustrative Mathematics
Right Triangles Inscribed in Circles II
So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be a...
Curated OER
Finding the Area of an Equilateral Triangle
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
Curated OER
Symmetries of Rectangles
Learners explore mapping a rectangle onto itself using rigid motion concepts, geometric intuition and experimenting with manipulatives in a collaborative task.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Midpoint of a Line Segment
Twenty problems present a variety of problems working with various aspects of finding the midpoint of a line segment. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem...
Other
Git: What Is the Slope Intercept Form of a Line?
Not only does this site show what the slope-intercept form is, but it helps you find the slope and the intercept of a line. There is also additional information on parallel lines, parametric form, and the distance between two points.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice Problems: Point, Line, Planes, Angles
Practice using your graphing calculator for drawing and labeling points, lines, planes, and angles. If you get stumped or if you would like to check your work, then select the View Solution button, which is located directly under each...
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Relations and Functions
Hotmath provides 25 practice problems dealing with relations, functions, and their graphs. Each of the practice problems include a step-by-step guide for solving their Algebraic problem.
BBC
Bbc: Ks3 Bitesize: Constructions and Locus
This BBC Bitesize focuses on constructions and locus. To understand this activity, you must already know how to define perpendicular, bisect, and locus.
BBC
Bbc: Representing Data
This BBC Math Bite tutorial for line graphs, pictograms, and frequency polygons features an exam in which students draw and interpret statistical diagrams.