Shodor Education Foundation
Triangle Area
While the lesson plan 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...
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...
5280 Math
Triangle Area Patterns
Combine algebraic and geometric strategies to find solutions. The task asks learners to find the coordinates of a third vertex of a triangle to create a triangle with a specific area. The project is a set of seven problems that helps...
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...
EngageNY
Using Trigonometry to Determine Area
What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...
Alabama Learning Exchange
Triangle Area: No Height? Use the Sine
No height? No problem! Learners use their knowledge and a little help from GeoGebra to develop the Law of Sines formula. The Law of Sines helps to determine the height of triangles to calculate the area.
EngageNY
Perimeter and Area of Polygonal Regions in the Cartesian Plane
How many sides does that polygon have? Building directly from lesson number eight in this series, learners now find the area and perimeter of any polygon on the coordinate plane. They decompose the polygons into triangles and use Green's...
Curated OER
Area of a Triangle
Students solve the area of triangles. In this precalculus lesson, students are given two sides of a triangle and asked to calculate the area. They apply the law of sine and the side-angle-side area formula to solve.
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
Volume and Surface Area
Students explore volume and surface area. In this math instructional activity, students fill boxes with cubes to identify the volume of the boxes. Students discuss area.
Curated OER
Unit Squares and Triangles
This is an interesting geometry problem. Given the figure, find the area of a triangle that is created by the intersecting lines. The solution requires one to use what he/she knows about coordinate geometry, as well as triangle and angle...
Curated OER
Area of Triangle using the Semi-Perimeter and Radius
Students investigate the properties of circles. In this geometry lesson, students calculate the area and perimeter of a triangle. They identify the perimeter and radius length of a circle.
Curated OER
Areas of Polygons
Young mathematicians calculate the area of polygons in this algebra lesson. They find the determinant as they calculate the areas for triangles and quadrilaterals. They also use scalar multiplication to find the determinant.
Curated OER
Investigating Area Relationships
Learners investigate the area of various figures. They construct triangles and quadrilaterals using Cabri Jr. and discuss the relationships between different angles, side lengths, and figures.
Curated OER
Midsegments of a Triangle
Students analyze midsegments of triangles in this lesson plan. They use Cabri Jr. software to observe the relationships between interior angles and midsegments of triangles. Specific instructions for creating this lesson plan in Cabri...
Curated OER
Napolean Triangle
Students investigate the Napoleon triangle theory. In this polygon lesson, students differentiate between the boundary points, interior and lattice point of a polygon. They apply concepts of equilateral triangles to solve problems.
Curated OER
Areas of Trapezoids, Rhombuses and Kites
Students calculate the area of different polygons. In this geometry lesson, students find the area for trapezoids, rhombuses and kites.
Curated OER
Triangle Midsegment
Learn how to calculate the length and midsegments of triangles. Students differentiate between similar and congruent triangles. They create a spreadsheet with their findings.
Curated OER
Complex Area Problems
Students calculate the area of different polygons. In this geometry lesson, students find the area of complex polygons. They solve word problems using rates and distances.
Curated OER
Area of Rectangles and Triangles
Eighth graders practice calculating the perimeter of different shapes. As a class, they work together to calculate the area of rectangles and triangles using the proper formula. To end the lesson, they determine how many feet are in a...
Curated OER
Area of Composite Polygon
Eighth graders are shown a blueprint of a house and must determine the amount of carpet needed. In groups, they calculate the area of rectangles and triangles and apply them to the shapes in the blueprint. To end the lesson, they...
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...
Curated OER
Altitude, Median, and Angle Bisector of a Triangle
Learners investigate the special properties of an altitude, a median, and an angle bisector and explore how these special segments divide the area of a triangle. The dynamic nature of Cabri Jr. allows pupils to form and verify conjectures.
Curated OER
Area Formulas
Teach your pupils to calculate the area of different polygons. Learners create formulas to solve their problems. They use the TI navigator to graph their shapes and observe the change in area.