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...

What do you need to prove triangles are similar? Learners answer this question through a construction exploration. Once they establish the criteria, they use the congruence and proportionality properties of similar objects to find...

Identifying and verifying reproducible patterns in mathematics is an essential skill. Mathematicians identify the relationship of sides when an angle is bisected in a triangle. Once the pupils determine the relationship, they prove it to...

Determine whether two triangles are similar. The lesson plan presents opportunities for pupils to find the criterion needed to show that two triangles are similar. Scholars use the definition of similarity to find any missing side...

Breaking the law in math doesn't get you jail time, but it does get you a wrong answer! After developing the Law of Sines and Cosines in lesson 33 of 36, the resource asks learners to apply the laws to different situations. Pupils must...

How do you solve an equation like trigonometry? Learners apply their understanding of trigonometric ratios to find unknown angles in right triangles. They learn the meaning of arcsine, arccosine, and arctangent. Problems include...

Viewers are presented with seven problems with parallel lines and angle relationships and must use the given information to find the measures of specific angles. To finish, they explain their process in finding the measures in the...

Amaze your classes with the ability to find side lengths of triangles immediately — they'll all want to know your trick! Learners use the Pythagorean Theorem and special right triangle relationships to find missing side lengths.

Fourth and fifth graders study the Pythagorean Theorem and apply it to find the missing side of a right triangle.

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. 

Use the Law of Cosines and the Law of Sines to solve problems using the sums of vectors. Pupils work on several different types of real-world problems that can be modeled using triangles with three known measurements. In the process,...

In this geometry instructional activity, students identify the missing sides and angles of triangles. They find the midsegment of each triangle. There are nine questions with an answer key.

Eighth graders find missing angles of triangles, quadrilaterals and angles formed by parallel lines cut by a transversal. They use area formulas to find the area of a figure; find the complement and supplement of a given angle; and know...

Your visual geometry learners will appreciate triangle drawings as they model the triangle sum theorem and algebraically solve to find the missing interior angle in a triangle. Practice problems increase in complexity and vary in their...

In this triangle worksheet, students find the missing angle in a set of 4 triangles. Answers are included on page 2. A reference web site is given for additional activities.

Can your classes apply the knowledge they have learned? Use this performance task to find out! Individuals use transformations to explain congruence and angle relationships within parallel lines to find missing values. They show what...

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...

Teach your class how to solve problems using the triangle sum theorem. In this geometry lesson, students identify the missing angles in a triangle using the sum theorem. They graph triangles on the TI and moves the sides around to create...

In this triangles worksheet, students solve for the missing angles and missing sides on the triangles given. Students complete 12 problems total.

In this special triangles instructional activity, students examine given special triangles.  They determine the length of a missing side and/or the measurement of a missing angle for given triangles and quadrilaterals. ...

In this trigonometric ratios worksheet, students solve 20 short answer and multiple choice problems.  Students use trigonometric ratios, the angle of depression, and angle of elevation to find missing side lengths of angles of a...

In this geometry worksheet, learners solve questions dealing with angles, triangles, and quadrilaterals. They calculate the missing angle. There are 2 questions.

Your class will investigate the relationship among different triangles. This geometry lesson, demonstrates how to make a connection between triangles and the Pythagorean Theorem. They identify the missing side or angle of a triangle.

In this applied trigonometry problems worksheet, learners solve 12 short answer word problems. Students use trigonometric ratios to find angles of elevation and depression. Learners find distances between objects using trigonometric...