Curated OER
How Do You Find Missing Angles in a Triangle With Variables?
Are you working on finding the missing angles in triangles in your class? Consider this video. An instructor uses the triangle sum theorem to create an equation that helps her find the missing angles. She explains each step and writes...
Curated OER
How Do You Find Missing Angles in a Triangle With Variables?
Are you working on finding the missing angles of triangles in your class? Consider this video. An instructor uses the triangle sum theorem to create an equation that helps her find the missing angles. She explains each step and writes...
Curated OER
How Do You Find a Missing Angle in a Quadrilateral?
Oh no, there is a missing angle in a quadrilateral. Where did it go? It didn't go anywhere, it's just missing the value of the angle. So how do you find that missing value? Use a formula of course. Everything in algebra uses a formula....
Curated OER
How Do You Find a Missing Angle in a Triangle?
The interior angles of any and ALL triangles adds up to 180 degrees. So if given two of the angle degrees, is it possible to find the value of the third angle? Yes! Use the triangle sum theorem to solve for the missing angle. Watch this...
Mathed Up!
Angles in Triangles and Quadrilaterals
This short video show viewers how to connect the sum of the angles in a triangle to other angle measurements. Pupils determine the missing measures for angles involved with triangles and quadrilaterals. Class members then must explain...
Curated OER
How Do You Find the Sine of an Angle in a Right Triangle?
A trigonometric ratio is a ratio between two sides of a right triangle. In this problem, find sin(A) in the given right triangle. Use the ratio of the opposite side over the hypotenuse.
Curated OER
How Do You Find Missing Angles in an Isosceles Triangle?
Finding the missing values of two angles in an isosceles triangle is not as difficult as it sounds. But how can two out of three angle's measurements be found? Well, there are special properties about an isosceles triangle which make...
Curated OER
How Do You Find a Missing Angle in a Right Triangle?
The triangle sum theorem states that the interior angles of a triangle add up to 180 degrees. So it seems logical that if there are two known values given for the interior angles of a triangle, the third value could be found using this...
CK-12 Foundation
The Third Angle Theorem: Lesson
If two sets of angles are equal, the third set is too. An informative portion of a playlist on geometry develops the Third Angle Theorem for triangles. Using the theorem, the presenter shows how to determine the measure of missing angles...
Curated OER
Why Are the Angles of Equilateral Triangles Always Equal to 60¼?
Learn how to identify an equilateral triangle by evaluating its congruent sides. Once you've determined that that sides are congruent you'll be able to use the triangle sum theorem to determine the angles in an equilateral triangle. This...
Curated OER
How Do You Find Missing Angles in an Isosceles Triangle Using Right Triangles?
Given an isosceles triangle, and the value of one angle, find the missing values. There are some special properties about isosceles triangles. Use the triangle sum theorem to solve this problem. Watch this video to see how the instructor...
Curated OER
How Do You Find the Tangent of an Angle in a Right Triangle?
What's a trigonometric ratio? It is a ratio between two sides of a right triangle. In this problem, find tangent(A) in the given right triangle. Use the ratio of the opposite side divided by the adjacent side to find tan(A). The...
CK-12 Foundation
Proportions with Angle Bisectors: Lesson
Half at one end becomes proportional on the other. As part of a basic geometry playlist, the video introduces the Angle Bisector Theorem. The presentation uses the theorem to find missing lengths in triangles.
Corbett Maths
Angles in a Triangle
The third angle's the charm. Viewers of a short video learn how to find the measure of the missing angle in a triangle. It uses an arithmetic process rather than an algebraic one, so younger learners have no trouble understanding the...
Brightstorm
Triangle Angle Sum
Don't believe everything that you hear — make them prove it! The video shows two methods to prove the Triangle Angle Sum Theorem. The following two videos apply the theorem to finding missing angle measures.
Flipped Math
Parallel Lines and Triangles
Triangles bring sums to geometry. The lesson presents two theorems dealing with the angles of a triangle. Pupils learn about the Triangle Sum Theorem and the Exterior Angle Theorem, and then apply the theorems to create equations and...
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
What are Complementary Angles?
Supplementary, obtuse, acute, complementary angles. It's good to know what all of these mean, but let's focus on one at a time. Complementary angles always add up to 90 degrees. So if given one angle in a complementary angle problem, the...
Math Antics
Triangles
What has three sides and is adorable? A-cute triangle. The resource introduces triangles and how to classify them by sides and angles or both. The video concludes with using the sum of the angles of a triangle to show how to solve for a...
Curated OER
How Do You Find the Cosine of an Angle in a Right Triangle?
What's a trigonometric ratio? It is a ratio between two sides of a right triangle. In this problem, find cosine(A) in the given right triangle. Use the ratio of the adjacent side divided by the hypotenuse to find cos(A). The instructor...
Curated OER
How Do You Find the Angles in a Triangle if You Have a Ratio of Their Measures?
Use the Triangle Sum Theorem to find the value of each of the inside angles of a triangle. This triangle problem has to do with the ratio of the angles to each other. Find the measure of each angle if the ratio is 1:3:8. Not sure how to...
Curated OER
How Do You Use Complementary Angles to Find a Missing Angle?
Are complementary angles nice to each other? That's not what complementary means in math. Complementary angles are two angles that add up to 90 degrees and form a right triangle. So if given one value in a problem about complementary...
Curated OER
How Do You Find a Missing Side of a Right Triangle Using Sine?
What's a trigonometric ratio? It is a ratio between two sides of a right triangle. In this problem, find sin(A) in the given right triangle. Use the ratio of the opposite side divided by the hypotenuse to find sin(A). The instructor...
FuseSchool
SOHCAHTOA - Finding Missing Angles
Apply the trig ratios to find unknown angle measures. Learners review the side and angle relationships in right triangles and then apply the ratios to find the angle measures. The video shows several worked-out examples applying all...