Curated OER
Find Missing Angles of Triangles
In this triangles worksheet, students find the missing angles of a set of 4 triangles. Answers are included on page 2.
EngageNY
Similarity and the Angle Bisector Theorem
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...
EngageNY
The Definition of Sine, Cosine, and Tangent
Introduce your classes to a new world of mathematics. Pupils learn to call trigonometric ratios by their given names: sine, cosine, and tangent. They find ratios and use known ratios to discover missing sides of similar...
Mathed Up!
Angles: Parallel Lines
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...
Curated OER
Triangles
In this triangles worksheet, learners solve for the missing angles and missing sides on the triangles given. Students complete 12 problems total.
Curated OER
Trigonometric Functions of Acute Right Triangles
Students derive the six trigonometric functions. In this trigonometry lesson, students show their understanding of trigonometric functions as they relate the right triangles. They find the missing angles and side use trig ratios of sine,...
Curated OER
Area Measures and Right Triangles
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.
Curated OER
Geometry Worksheet- Angle
In this geometry worksheet, students solve questions dealing with angles, triangles, and quadrilaterals. They calculate the missing angle. There are 2 questions.
EngageNY
More About Similar Triangles
Determine whether two triangles are similar. The lesson 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...
EngageNY
Special Relationships Within Right Triangles—Dividing into Two Similar Sub-Triangles
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...
EngageNY
Unknown Angle Problems with Inscribed Angles in Circles
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...
Curated OER
Determine the Measure of an Angle of a Right Triangle.
In this geometry worksheet, students solve word problems by finding the values of missing angles and missing sides of triangles. They review their trigonometric properties of a right triangle. There are 9 problems with an answer key.
EngageNY
Law of Sines
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...
Flipped Math
Prove Triangles Similar
Show more than one way to prove similarity. Scholars learn three different methods to show two triangles are similar, Angle-Angle, Side-Side-Side, and Side-Angle-Side. Pupils practice applying these methods to determine whether two given...
Curated OER
Right Triangle Trigonometry: Evaluating Trigonometric Ratios
In this right triangle trigonometry worksheet, students use trigonometric ratios to determine the length of a missing side of a triangle or to find a specified angle measurement. This four-page worksheet contains 32 problems. Answers are...
Curated OER
Angles in Polygons
For this angles in polygons worksheet, learners determine the value of a missing angle measure. They find the value of interior angles and exterior angles. Polygons include triangles, quadrilaterals, pentagons, and hexagons. This...
Curated OER
Isosceles Triangles
In this geometry worksheet, high schoolers set up equations to solve for the missing angle or side of an isosceles triangle. All the equations turn out to be linear and not quadratic. There are 15 questions.
Curated OER
You Can't Go Wrong with a Right Triangle 1
Fourth and fifth graders study the Pythagorean Theorem and apply it to find the missing side of a right triangle.
Curated OER
Trigonometric Triangles
In this trigonometry worksheet, students find the missing angle and sides given the 6 trigonometric values. There are 6 questions with an answer key.
Kim Brassard
Solving Right Triangles
Solve that triangle! Your class examines angles and side measurements on 20 right triangles to determine the missing measurements. For some, they are given two sides while for others, they are given an angle and a side.
Curated OER
Using Trinonometry to Find Angle Measures
In this trigonometric ratios worksheet, students find the missing angle of 20 triangles by using sine, cosine and tangent ratios. Students compute the angle measurement of given ratios for six problems.
Curated OER
Missing Angle Problems
In this problem solving worksheet, 6th graders focus on the angles described in each word problem. Students must solve for each of the 6 problems, giving a written explanation for each in the space provided.
Mathed Up!
Sine and Cosine Rules and Area of Triangles
Learners discover how to find missing sides and angles using trigonometry. Scholars first watch a video covering the Law of Sines and Cosines, as well as the area formula for a triangle. To test their knowledge, they complete a worksheet...
Curated OER
Special Segments in a Triangle
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...