Tenth graders explore parallel and perpendicular lines.  In this geometry lesson plan, 10th graders investigate the relationships associated with parallel lines and transversals, perpendicular lines, and the angles formed by these...

Tenth graders pretend to set up an ice cream shop in a make believe town of shapes.  In this geometry lesson plan, 10th graders work together to put up an ice cream stand in an ideal location and solve for the minimum given the shapes.

Tenth graders investigate the theorems of angles and lines to prove triagle sum theorem. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two...

Students investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson plan, students discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by two...

Students differentiate between inductive and deductive reasoning. In this geometry lesson, students identify congruent figures and examine logos for congruency.

Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...

Pupils work in pairs to investigate what it takes to prove that two triangles are similar. They work through various shortcuts to find which are enough to show a similarity relationship between the triangles. Small groups work with the...

Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...

Make the connection between the distance formula and the equation of a circle. The teacher presents a lesson on how to use the distance formula to derive the equation of the circle. Pupils transform circles on the coordinate plane and...

Don't be a square! Young mathematicians determine the slope and length of a line segment. They then prove whether four given coordinate points form a square.

In this points, lines and planes worksheet, 10th graders solve and complete 9 various types of problems. First, they name the planes that intersect a figure shown. Then, students determine the points that are collinear and coplanar in...

For this skills worksheet, students explain the Segment Addition Postulate, provide examples and counter examples and determine congruent line segments.  This one-page worksheet contains 11 multi-step problems.

Scholars first investigate relationships in the side lengths of 30°-60°-90° triangles and 45°-45°-90° triangles. This knowledge then helps them solve problems later in the lesson plan about special right triangles.

Inscribed angles are central to the lesson. Young mathematicians build upon concepts learned in the previous lesson and formalize the Inscribed Angle Theorem relating inscribed and central angles. The lesson then guides learners to prove...

What's so special about tangents? Learners first explore how if a circle is tangent to both rays of an angle, then its center is on the angle bisector. They then complete a set of exercises designed to explore further properties and...

Challenge scholars to prove the Pythagorean Theorem geometrically by using a cut-and-paste activity. They then must solve for the missing sides of right triangles.

How do 2-D properties relate in 3-D? Lead the class in a discussion on how to draw and see relationships of lines and planes in three dimensions. The ability to see these relationships is critical to the further study of volume and...

We know theorems about circles—now what? Class members prove a theorem, with half the class taking the case where a point is inside the circle and half the class taking the case where a point is outside the circle. The lesson then...

Triangles, triangles, and more triangles! In this second installment of a 36-part series, your young mathematicians explore two increasingly challenging constructions, requiring them to develop a way to construct three triangles that...

In this angle measures learning exercise, students solve 9 short answer problems. Students find values for x and y given two parallel lines cut by a transversal. Students use alternate interior, supplementary, and exterior angles to find...

In this postulates and theorems worksheet, students explore a concept map containing information about angles and sides, alternate interior angles, and diagonals of a parallelogram.  They use the concept map to prove theorems...

Students compute surface area and volume of prisms. In this surface area lesson, students find the surface area and volume of rectangular and triangular prisms. Independently, students use their computers to determine the volume,...

Students identify various geometric shapes. Apply the given formulas to determine the volume of these shapes. Design their own container to conform to specifications provided. Use their knowledge of volume formulas and shapes to compute...