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...
EngageNY
An Area Formula for Triangles
Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....
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...
Curated OER
Perimeter and Area 5
For this calculating area worksheet, students use their problem solving skills and the information provided to find the area of 6 triangles.
Curated OER
Two Triangles' Area
Need an activity for teaching the Pythagorean Theorem? Geometry juniors apply the Pythagorean theorem to two triangles to determine a final calculation.
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.
Government of Hong Kong
Areas and Volumes - 2D Shapes
Unfortunately for young mathematicians, the world isn't made entirely of parallelograms, triangles, and trapezoids. After first learning the area formulas for these common shapes, students apply this new knowledge to determine the area...
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...
Alabama Learning Exchange
Polygons-Changing Area Versus Changing Perimeter
Investigate the area and perimeter of polygons in this geometry lesson. Young geometers use grid paper to draw a quadrilateral and calculate its area and perimeter. They also read The Greedy Triangle to identify the changing shape of...
Curated OER
Area of Tangram Pieces
Mathematicians calculate the area of a tangram piece without using formulas. They use a geometry journal to record activities during this lesson. They make a set of tangrams and use them to compute area. They use what they discover to...
Curated OER
Measure: Perimeter, Area and Volume
Students practice measuring with formulas. In this measurement lesson, students complete an activity that requires them to calculate perimeter, area, and volume.
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...
Curated OER
Perimeter and Area 8
In this calculating area worksheet, young scholars use their problem solving skills and the information provided to find the area of 6 triangles.
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...
Willow Tree
Surface Area of Three-Dimensional Figures
Lateral area and surface area are simple concepts, but calculating them is not as easy! Using formulas, learners calculate lateral area and surface area for the same three-dimensional figures. The resource discusses the formula variables...
EngageNY
The Scaling Principle for Area
As they investigate scaling figures and calculate the resulting areas, groups determine the area of similar figures. They continue to investigate the results when the vertical and horizontal scales are not equal.
Curated OER
Area of a Triangle
Students solve the area of triangles. For 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
Algebra/Geometry Institute Summer 2009 - Triangles and the Pythagorean Theorem
Seventh graders find the perimeter and area of triangles. In this finding the perimeter and area of triangles lesson, 7th graders find the perimeter and area of triangles given two sides. Students find the missing side by using the...
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 by Logic - Total Surface Area
Geometers calculate the area of plane surfaces using the formulas for the area of a square, rectangle, and triangle. They develop the formula for calculating the total surface area of two geometric solids: the cube and rectangular prism.
Curated OER
The Luxor - Pyramids, Surface Area & Volume
Students investigate the surface area and volume of the Luxor Hotel in Las Vegas. They calculate the slant height, lateral edge, and diagonal length of the base. Using this information, students explore other areas of the hotel, such as...
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...