Young mathematicians explore the concept of triangles as they construct altitudes of triangles to find the orthocenter. Learners construct their triangles using Cabri Jr. on their graphing calculators and find that the altitudes of a...

Learners investigate the special properties of an altitude, a median, and an angle bisector and explore how these special segments divide the area of a triangle. The dynamic nature of Cabri Jr. allows pupils to form and verify conjectures.

Here is a straightforward example of how to apply the Pythagorean Theorem to find an unknown side-length of a trapezoid. Commentary gives additional information on proving that the inside of the trapezoid is a rectangle, but is...

Medians, midsegments, altitudes, oh my! Pupils study the properties of the median of a triangle, initially examining a proof utilizing midsegments to determine the length ratio of a median. They then use the information to find missing...

For this geometry worksheet, 10th graders determine if a given segment is a median or altitude of a triangle and use then find the indicated missing length or equation of a line.  The two page worksheet contains twenty...

In this geometry worksheet, 10th graders review the vocabulary associated with the special segments of a triangle and the associated points of concurrency and solve problems in which they find the indicated missing angle or...

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...

Prove the Law of Sines two ways. The ninth segment in a series of 16 introduces the Law of Sines to help the class find lengths of sides in oblique triangles. Pupils develop a proof of the Law of Sines by drawing an altitude and a second...

Students find the orthocenter of a triangle. In this geometry lesson, students identify where the altitudes meet in a triangle. They use Cabri software to explore acute, obtuse and right triangles.

Middle and high schoolers investigate all the different places in math that square root is present. For this geometry lesson, pupils discuss square roots as it relates to a right triangle and construction. They go over altitude, rise,...

What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...

Why are right triangles so special? Pupils begin their study of right triangles by examining similar right triangles. Verifying through proofs, scholars recognize the three similar right triangles formed by drawing the altitude. Once...

This is a good model for learners to visualize triangles of the same base and height. They can can begin to comprehend that these triangles will have the same area no matter how the triangle is drawn. It is part of a series of resources...

Not all triangles are right! Pupils learn to tackle non-right triangles using the Law of Sines and Law of Cosines. After using the two laws, they then apply them to word problems. 

Students identify important properties of triangles. For this geometry lesson, students differentiate between medians, bisectors and altitudes in a triangle. They identify the properties of these important segments.

Students calculate the area of a parallelogram. In this geometry instructional activity, students perform translation using a coordinate plane and coordinate pairs. They perform translation on other polygons.

Students calculate the altitude of triangles.  In the web based lesson, students explore the interior distance from a given point in a polygon to its side.  They compute the sum of these lengths. Students read life...

Students calculate the area of parallelograms. In this geometry lesson, students identify properties of parallelograms and use to to solve problems. They create polygons using Cabri software.

For this geometry worksheet, young scholars differentiate between regular triangles and isosceles triangles. They apply the converse theorem and the vertex angle. There are eleven questions with an answer key.

Transform your pupils into mathematicians as they learn to prove the popular Pythagorean Theorem. The 16th lesson in the series of 25 continues by teaching learners how to develop a proof. It shows how to prove the Pythagorean Theorem...

Students examine what iridium flares are and when they occur.  In this iridium flare lesson students complete an activity to see how far overhead Iridium satellites are.

Students draw and calculate altitudes. They draw the altitude of acute, right and obtuse triangles and calculate the altitude of a triangle using the Pythagorean theorem.

Students calculate the height and altitude of a pyramid. In this geometry lesson, students define the parts that make up a pyramid. They use the Pythagorean Theorem to find the missing parts of a pyramid.

Students identify the special segments of triangles, the median, angle bisector, altitude, and perpendicular bisectors.