Lesson Plan
Curated OER

Ratios in Right Triangles

For Teachers 9th - 12th Standards
Learners calculate the sides of right triangles in this trigonometric ratios lesson. They use Cabri Jr. software and TI-83 or TI-84 calculators to find the side lengths and their ratios to each other for various triangles. The provided...
Lesson Plan
Curated OER

Similar Triangles and Proportions

For Teachers 9th - 12th Standards
Pupils investigate similar triangles and proportions as they make conjectures about the length of sides of similar triangles. For this lesson, have your class construct similar triangles using Cabri Jr so that they share a common vertex.
Lesson Plan
Curated OER

Triangle Inequality Theorem

For Teachers 9th - 12th Standards
High schoolers investigate the relationship between angle measures and sides of a triangle and the relationships among the three sides of a triangle. The use of technology (Cabri, Jr.) allows learners to make and test conjectures as they...
Lesson Plan
Curated OER

30-60-90 Right Triangles in Cabri Jr.

For Teachers 9th - 12th Standards
Young mathematicians draw and label right triangles using Cabri Jr. technology. They create other special right triangles and identify the length of the hypotenuse and each leg. Young scholars explore the ratios to determine how the...
Lesson Plan
Curated OER

Area of a Triangle

For Teachers 10th - 11th
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.
Lesson Plan
Curated OER

Area Measures and Right Triangles

For Teachers 9th - 12th Standards
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.
Lesson Plan
Curated OER

Triangle Midsegment

For Teachers 9th - 12th Standards
Learn how to calculate the length and midsegments of triangles. Students differentiate between similar and congruent triangles. They create a spreadsheet with their findings.
Lesson Plan
Curated OER

Nested Similar Triangles

For Teachers 9th - 12th Standards
Nested triangles have been created so that they share a common vertex and vertex angle. Learners drag the endpoints of the side that is opposite the common angle to discover the conditions that make the nested triangles similar. When...
Lesson Plan
Curated OER

Circumscribing a Circle About a Triangle

For Teachers 9th - 12th Standards
Pupils circumscribe a circle about a triangle. They construct a triangle using Cabri Jr and then circumscribe it. They then use knowledge of perpendicular bisectors and circumcenters to locate the center of the circle and then...
Lesson Plan
Curated OER

Exploring the Circumcenter of a Triangle

For Teachers 9th - 12th Standards
Students construct the circumcenter of a triangle. For this constructing the circumcenter of a triangle lesson, students construct a triangle using Cabri Jr. Students draw perpendicular bisectors of the sides of the triangle. Students...
Lesson Plan
Curated OER

Exploring the Orthocenter of a Triangle

For Teachers 9th - 12th Standards
Young mathematicians explore the concept of triangles as they construct altitudes of triangles to find the orthocenter. Learners construct their triangles using Cabri Jr. on their graphing calculators and find that the altitudes of a...
Lesson Plan
Curated OER

Midsegments of a Triangle

For Teachers 9th - 12th Standards
Students analyze midsegments of triangles in this instructional activity. They use Cabri Jr. software to observe the relationships between interior angles and midsegments of triangles. Specific instructions for creating this...
Lesson Plan
EngageNY

Unknown Area Problems on the Coordinate Plane

For Teachers 7th Standards
Scholars determine distances on the coordinate plane to find areas. The instructional activity begins with a proof of the formula for the area of a parallelogram using the coordinate plane. Pupils use the coordinate plane to determine...
Lesson Plan
Beyond Benign

Hit the Deck: Area and Perimeter Review

For Teachers 6th - 8th
Designing a deck sure demands a lot of math. Future engineers and architects learn about the areas and perimeters of squares, rectangles, triangles, and composite figures. They apply their new knowledge to design a deck with a specified...
Lesson Plan
Curated OER

Perimeter and Area 8

For Teachers 5th - 7th
In this calculating area worksheet, students use their problem solving skills and the information provided to find the area of 6 triangles.
Lesson Plan
Curated OER

Algebra/Geometry Institute Summer 2009 - Triangles and the Pythagorean Theorem

For Teachers 7th
Seventh graders find the perimeter and area of triangles.  In this finding the perimeter and area of triangles lesson plan, 7th graders find the perimeter and area of triangles given two sides.  Students find the missing side...
Lesson Plan
Curated OER

Geometry Practice: Area of Polygons #8

For Teachers 9th - 12th
In this area of polygons worksheet, students solve 7 short answer and multiple choice questions about area.  Students find the area of triangles given base and height, or points in the coordinate plane.
Lesson Plan
Curated OER

Areas of States - Estimation

For Teachers K - 8th
Students estimate the area of states using the formulas for the areas of rectangles, squares, and triangles. In this geometric shapes lesson plan, students divide irregular shaped states into shapes. They use the formulas for areas of...
Lesson Plan
Curated OER

Area of Rectangles and Triangles

For Teachers 8th
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 activity, they determine how many feet are in...
Lesson Plan
Curated OER

Review Geometry - Week 8 (Triangles)

For Teachers 11th - 12th
In this triangle worksheet, students use similar figures to find the length of one side of two similar triangles. They find the area of a triangle inscribed in a rectangle. This two-page worksheet contains eight problems.
Lesson Plan
Curated OER

Exploring Centers of a Triangle: Part 2

For Teachers 10th - 12th
Students model and solve a real-world problem by constructing the centroid of a triangle. They explore relationships of the medians of a triangle and investigate how the centroid partitions each of the medians. Students investigate...
Lesson Plan
Curated OER

Areas of Trapezoids, Rhombuses and Kites

For Teachers 8th - 10th
Students calculate the area of different polygons. In this geometry lesson, students find the area for trapezoids, rhombuses and kites.
Lesson Plan
Curated OER

Special Segments of Triangles Jigsaw Activity

For Teachers 11th - 12th
Students identify the special segments of triangles, the median, angle bisector, altitude, and perpendicular bisectors.
Lesson Plan
Curated OER

Napolean Triangle

For Teachers 9th - 11th
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...

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