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....
Curated OER
Secret Formulas
Learners calculate the perimeter of rectangles and squares. They imagine trying to build a fence around a yard or trying to determine how much paint they need to paint a room. They also develop formulas and procedures for determining the...
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.
Virginia Department of Education
Surface Area and Volume
Partners use materials to wrap three-dimensional objects to determine the formula for surface area. The groups use an orange to calculate the amount of peel it takes to completely cover the fruit. Using manipulatives, individuals then...
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...
Discovery Education
Discovering Math: Exploring Geometry
Apply geometric properties and formulae for surface area and volume by constructing a three-dimensional model of a city. Learners use similar and congruent figures and transformations to create a city of at least 10 buildings. They trade...
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...
EngageNY
The Volume Formula of a Sphere
What is the relationship between a hemisphere, a cone, and a cylinder? Using Cavalieri's Principle, the class determines that the sum of the volume of a hemisphere and a cone with the same radius and height equals the volume of a...
Curated OER
Connecting Formulas Related to Geometric Figures
Students identify diagrams of quadrilaterals and circles by different names and classify the figures. They name the areas for each diagram and practice solving the formulas for each.
Texas Instruments
Area of Circles
Students explore circles. In this algebra/geometry lesson, students discover the formula for the area of a circle, as they investigate the ratio of the area of a circle to the radius^2.
Curated OER
Finding Perimeter and Area
Geometers find the perimeter and area of rectangles. They discuss the definitions and characteristics of rectangles and squares. In groups, they use yarn to discover the perimeter of squares and rectangles. They count cubes to explore...
Curated OER
Area and Perimeter of Rectangles
Discover the difference between area and perimeter. Learners are grouped in twos and threes and each group has one advanced/gifted learner to serve as the peer helper. They receive manipulatives to help them determine the area and...
Curated OER
Gotcha Covered, Pardner!
Young geometers use the interactive website Cyberchase to practice calculating both area and perimeter. Real world problems encourage learners to discover that we use math each and every day.
Curated OER
Volume and Surface Area: Which Is More?
Learners explore the volume and surface area of three dimensional figures. Through the use of video, students discover three dimensional shapes, their uses in real-life applications, and methods used to calculate their volume and surface...
Curated OER
Geometry: Area Project
Sixth graders identify and use area formulas for finding the area of geometric shapes.
Curated OER
Finding Patterns in Tiles
Students explore perimeter and area of rectangles. In this rectangular lesson, students use tiles to discover the formulas for perimeter and area. Students solve for area.
Curated OER
Changing Twines: Exploring Area and Perimeter
Third graders review formulas for area and perimeter in quadrilaterals. They arrange pre-cut twine on a centimeter graph paper to create non-congruent quadrilaterals. They calculate the perimeter and area of each form.
Curated OER
Finding Areas of Plane Figures
Learners compute areas of squares, rectangles, and so on and summarize the formulas for computing areas and explain how the formulas are derived and understand the reasoning behind them.
Curated OER
Robot Area
Students calculate the area of different polygons. For this geometry lesson, students explore polygons based in their shape and number of sides. They find the formula for the area and use each specific formula for each shape.
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.
TryEngineering
Exploring at the Nanoscale
Discover a world too small to see. In the lesson, young scientists learn about nanotechnology and brainstorm ideas for new applications of it. They perform an activity to determine how surface area changes when objects are made smaller...
EngageNY
Getting a Handle on New Transformations 1
In the first of a two-day activity on transformations with matrix notation the class transforms the unit square using general transformations, then calculates the area of the transformed image. They discover it is the same as...
Curated OER
Area and Perimeter
Learners discover and apply the formula for the area and perimeter of rectangles and squares. They draw the shapes on graph paper and create tables that include their information.
Curated OER
Cover and Boarders
Students find the area and perimeter of rectangular figures. They use this information to find patterns and discover relationships between area and perimeter. Students apply and explain formulas relating to perimeter, area, and volume.