Curated OER
Area of Right-Angled Triangles
There's a trick to solving the area of a triangle, and it involves a skill your geometers have already mastered. Help them discover the connection between finding a rectangle's area and finding a right triangle's area as they solve for...
Scholastic
Study Jams! Area of a Triangle
Even though there is a wide variety of different triangles in the world, knowing a single equation allows us to find the area of each and every one of them. Follow along with this step-by-step presentation as Zoe clearly models how to...
Shodor Education Foundation
Triangle Area
While the lesson focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can they...
Curated OER
Area of Right Triangles
In this are of right triangles worksheet, students read graphs and explore congruent triangles. They find the area of rectangles and of right triangles. This one-page worksheet contains explanations, instructions, and 8 problems.
Curated OER
Finding the Area of an Equilateral Triangle
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
Illustrative Mathematics
Finding Areas of Polygons, Variation 1
An exercise in finding the area of polygons by decomposing into triangles and composing into rectangles is the focus of this resource. Make several copies of the worksheet for each participant. Ask learners to use colored pencils to...
Illustrative Mathematics
Area of a Trapezoid
Here is a straightforward example of how to apply the Pythagorean Theorem to find an unknown side-length of a trapezoid. Commentary gives additional information on proving that the inside of the trapezoid is a rectangle, but is...
Noyce Foundation
Lyle's Triangles
Try five problems on triangles. Levels A and B focus on shapes that can be created from right triangles. Level C touches upon the relationship between the area of a six-pointed star and the area of each triangle of which it is composed....
Curated OER
Right Triangles
In this right triangles worksheet, 10th graders solve and complete 5 various types of problems. First, they solve each of the triangles shown and find the area of each triangle. Then, students find the perimeter and area of the regular...
Illustrative Mathematics
Same Base and Height, Variation 2
This is a good model for learners to visualize triangles of the same base and height. They can can begin to comprehend that these triangles will have the same area no matter how the triangle is drawn. It is part of a series of resources...
Illustrative Mathematics
Base and Height
It is easy to find the area of a triangle where the base and the height are given. But in this resource, it is up to your geometers to identify the base and height of the triangle. In fact, your pupils will learn that there are three...
Inside Mathematics
Circles in Triangles
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
Shodor Education Foundation
Squaring the Triangle
Teach budding mathematicians how to square a triangle with an interactive that shows a graphical proof of the Pythagorean Theorem. Pupils alter the lengths of the legs using sliders. Using the inputted lengths, the applet displays the...
Alabama Learning Exchange
What You Know About the Bermuda Triangle?
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
Curated OER
Pythagorean Theorem
In this measurement lesson plan, learners examine the Pythagorean Theorem, perimeter, and areas of right triangles. They record their measurements and research their findings on a grid.
CK-12 Foundation
Area Between Curves: Income and Expenses
Use the area of polygons to calculate the area between curves. Pupils calculate areas under income and expense curves by filling the space with squares and right triangles. Using that information, they determine the profit related to the...
Curated OER
Triangles
This unit enables scholars to apply the rule for area of a triangle (area equals half base times height). They practice multiplication and division strategies as they calculate areas.
Curated OER
Principles of Square Roots Lesson Plan
Middle and high schoolers investigate all the different places in math that square root is present. In this geometry lesson, pupils discuss square roots as it relates to a right triangle and construction. They go over altitude, rise,...
Curated OER
Learning Unit: The Pythagorean Theorem
Middle and high schoolers research the life of Pythagoras and the Pythagorean theorem. They write a short biography of Pythagoras and learn to apply the theorem in their study of right triangles.
Curated OER
Mixed Right Triangles
In this geometry activity, 10th graders use right triangle trigonometry to find the missing angle measure or side length in right triangles. The one page interactive activity contains ten questions. Answers and hints are included.
Curated OER
Finding the Area and Perimeter of Polygons
Seventh graders practice finding the area and perimeter of polygons. In this polygon area lesson, 7th graders brainstorm shapes and take a walk to locate shapes. Students record properties of shapes and use various shapes to make a...
EngageNY
Perimeter and Area of Triangles in the Cartesian Plane
Pupils figure out how to be resourceful when tasked with finding the area of a triangle knowing nothing but its endpoints. Beginning by exploring and decomposing a triangle, learners find the perimeter and area of a triangle. They then...
Alabama Learning Exchange
Polygons-Changing Area Versus Changing Perimeter
Investigate the area and perimeter of polygons in this geometry instructional activity. Young geometers use grid paper to draw a quadrilateral and calculate its area and perimeter. They also read The Greedy Triangle to identify the...
Curated OER
Roofing and Right Triangles
Students use models and symbols to represent properties of the Pythagorean Theorem. In this right triangle lesson plan, students connect real jobs to properties of right triangles. They solve word problems applying the correct ratios and...