Alternate Interior Angles
Explore the relationships of the angles formed when two parallel lines are cut by a transversal.https://education.ti.com/en/activity/detail/alternate-interior-angles
Altitudes of Triangles
Students investigate the intersection of the altitudes of a triangle.https://education.ti.com/en/activity/detail/altitudes-of-triangles
Mystery Quadrilateral!
This activity could be used as an assessment after a unit on special quadrilaterals. Students are given an unknown mystery quadrilateral that looks like a square. By dragging the vertices of the mystery quadrilateral, students conjecture the true name of the quadrilateral. Students support their ...https://education.ti.com/en/activity/detail/mystery-quadrilateral
Angle and Perpendicular Bisectors in a Triangle
The students will examine where the perpendicular bisectors and angle bisectors of a triangle intersect. The students will circumscribe a circle around the triangle and will inscribe a circle within the triangle. There is a page at the end of each activity with the circle constructed if the s...https://education.ti.com/en/activity/detail/angle-and-perpendicular-bisectors-in-a-triangle
Angles & Chords in a Circle
This activity is designed to allow students to gain an understanding of the relationship between the arcs and angles formed by intersecting chords in a circle. It includes an interactive geometry page, some circle problems, and a Euclidean proof.https://education.ti.com/en/activity/detail/angles--chords-in-a-circle
Nested Similar Triangles
Discover the conditions that make triangles similar by moving the sides opposite the common angle in nested triangles.https://education.ti.com/en/activity/detail/nested-similar-triangles
Triangle: Side Lengths and Angle Measures
The main purpose of this activity is to allow students to use TI-Nspire or TI-Nspire CAS to explore and decide which sides and angles of a triangle are the smallest and which are the largest.https://education.ti.com/en/activity/detail/triangle-side-lengths-and-angle-measures
The Flag Problem
Students explore the area of a triangle with the base being one of the legs of a right angled trapezoid, and an opposite vertex being a point on the other leg of the trapezoid.https://education.ti.com/en/activity/detail/the-flag-problem
The Geometric Mean
In this activity, students will establish that several triangles are similar and then determine that the altitude to the hypotenuse of a right triangle is the geometric mean between the segments into which it divides the hypotenuse.https://education.ti.com/en/activity/detail/the-geometric-mean_1
The Hinge Theorems
Students will explore the inequality relationships that arise when some of the triangle congruence conditions are in place but others are not. The SAS Inequality Theorem and the SSS Inequality Theorem are often referred to as the Hinge Theorem and its converse. These two theorems concern inequali...https://education.ti.com/en/activity/detail/the-hinge-theorems_1
Regular Polygons - Angle Measurements
Students will investigate the number of degrees in each polygon with three through ten sides, then develop a formula for the relationship between the number of sides and the sum of the measures of the degrees of the polygons.https://education.ti.com/en/activity/detail/regular-polygons--angle-measurements
The Ladder Problem Revisited
In this activity students explore the locus of mid-point of the hypotenuse of a fixed length geometrically and algebraically and discover that the median a right triangle is equal to half the length of the hypotenuse. Students then prove this property. The problem: A ladder leans upright against ...https://education.ti.com/en/activity/detail/the-ladder-problem-revisited
The Lunes of Hippocrates
In this activity the students discover a property of this historical figure.https://education.ti.com/en/activity/detail/the-lunes-of-hippocrates
Pythagorean Relationships
Investigate the triangles that can be formed using one side of three squares to build the triangle.https://education.ti.com/en/activity/detail/pythagorean-relationships
The Magic of Central Angles
This activity allows students to investigate the relationship between central angles and the arcs they intercept.https://education.ti.com/en/activity/detail/the-magic-of-central-angles
Pythagorean Triples
Explore Pythagorean triples by dragging vertices to find whole number Pythagorean triples.https://education.ti.com/en/activity/detail/pythagorean-triples
The Pirate Problem
The classic geometry problem developed in 1947 by George Gamow comes alive with the interactive platform of TI-Nspire. Will the treasure still be found after the palm tree in the treasure map disappears? What begins with inductive reasoning ends with a formal proof. This lesson, easily adapte...https://education.ti.com/en/activity/detail/the-pirate-problem
The Pythagorean Theorem—and More
Students construct a triangle and find all angle and side measures. They practice dragging the vertices to form certain types of triangles, and then they confirm the Pythagorean Theorem for right triangles. Moreover, they discover the types of triangle that occur when c2 a2 + b2 or when c2 > a2 +...https://education.ti.com/en/activity/detail/the-pythagorean-theoremand-more
Ratios of Similar Figures
Students explore the ratio of perimeter, area, surface area, and volume of similar figures in two and three dimensional figures.https://education.ti.com/en/activity/detail/ratios-of-similar-figures_1
The Lunes of Hippocrates
In this activity, students will explore a figure that involves lunes - the area enclosed between arcs of intersecting circles. When lunes are constructed on the sides of a right triangle, an interesting result occurs.https://education.ti.com/en/activity/detail/the-lunes-of-hippocrates_1
Reflections in Motion
Students will use reflected images of triangles to observe similarities retained under vertical and horizontal stretching and shrinking transformations.https://education.ti.com/en/activity/detail/reflections-in-motion
Supplements and Complements
The attached files contain a supplementary angle and complementary angle for students to explore. They are asked which point changes the measure of the angle. They can move various parts of the construction. The files are designed to be used with your current instructional materials.https://education.ti.com/en/activity/detail/supplements-and-complements
Secants and Angles in a Circle
This activity is designed to allow students to gain an understanding of the relationship between the arcs and angles formed by secants drawn from a common external point outside a circle. It includes an interactive geometry page, some circle problems, and a Euclidean proof.https://education.ti.com/en/activity/detail/secants-and-angles-in-a-circle
Sine. It's the Law.
Students will investigate the ratio of the sine of an angle to the length of the opposite side.https://education.ti.com/en/activity/detail/sine--its-the-law_1
SSA Ambiguity
This activity allows students to investigate the reason for the ambiguity in the SSA case.https://education.ti.com/en/activity/detail/ssa-ambiguity