One of the basic properties of inscribed angles gets a triangle proof treatment in a short but detailed exercise. Leading directions take the learner through identifying characteristics of a circle and how they relate to angles and...

A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...

Everyone's heard of Pythagoras, but who's Ptolemy? Learners test Ptolemy's Theorem using a specific cyclic quadrilateral and a ruler in the 22nd installment of a 23-part module. They then work through a proof of the theorem.

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...

Scholars determine distances on the coordinate plane to find areas. The instructional activity begins with a proof of the formula for the area of a parallelogram using the coordinate plane. Pupils use the coordinate plane to determine...

Using a similar process from the first lesson in the series of finding area approximations, a measurement resource develops the proof of the area of a circle. The problem set contains a derivation of the proof of the circumference...

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...

Ninth graders, after being given a unique scenario and a task sheet on Dead Man's Curve, calculate and explain the force needed to keep a car on a curve using a set of formulas and a geometric property of circles. They utilize and create...

Triangles, triangles, and more triangles! For 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 math worksheet, students find the length of the side of a regular hexagon whose area is numerically equal to its perimeter.

Students investigate the relationship between angles and their sides. In this geometry lesson, students prove why SSA does not work as a true angle side relationship theorem.

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...

Pupils examine a math worksheet and determine how to divide a single triangle into four of equal area. Using geometric principles, they sketch two additional ways to divide into into four equal triangles. To conclude, students explain...