Triangle Teacher Resources
Find Triangle lesson plans and worksheets
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Frog Garden Party! Toads and Triangles in the Math Garden
4th CCSS: Designed
It's frog party time! With frog banners, frog juice, and a triangle hunt, your garden party is sure to be both entertaining and educational. The lesson connects geometry, earth science, and delicious snacks to teach kids about ecosystems...
Find the Area of a Right Triangle
4 mins 5th - 7th CCSS: Designed
Help your class develop a greater understanding of the area of a right triangle. The video starts by reviewing the area of a rectangle and noting that the rectangle is made up of two congruent triangles. Learners are then shown that in...
The Mathematical Secrets of Pascal’s Triangle
5 mins 7th - 12th CCSS: Adaptable
This modern animation and discussion of the ancient secrets of Pascal's triangle manages to be topical, engaging, and mathematically deep all at the same time. A great introduction to the power of number theory across multiple math...
How Do You Determine if a Triangle Is a Right Triangle if You Know its Sides?
3 mins 6th - 10th
Use the Pythagorean Theorem formula to check if this given triangle, with the given lengths of each side, is a right triangle. It's as simple as plugging the given values into the formula and doing the math to see if the solution checks...
Mathematics Within: Slope and Triangles
8th - 10th CCSS: Adaptable
Learners discover a method for determining the slope of a line by creating and comparing similar triangles. They fold coordinate grids to make three similar triangles then measure the sides to compare the relationships between the...
The Angle-Angle (AA) Criterion for Two Triangles to Be Similar
9th - 10th CCSS: Designed
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...
Equilateral Triangles: Lesson
3 mins 8th - 11th CCSS: Adaptable
Take a second look at triangles that are equal all the way around. The video reminds viewers what an equilateral triangle is and points out that the three angles are the same. Using the fact that equilateral triangles are also isosceles,...
Similar Right Triangles and Trig Ratios
9th - 11th CCSS: Designed
Is it possible to be the same yet different? Absolutely! The activity asks learners to explore the relationships between side ratios of triangles they have drawn. Because individuals all draw a triangle with the same angle measures, they...