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....
Balanced Assessment
Fermi Area
Discover creative ways to use surface area formulas. In the assessment task, scholars apply estimation strategies to determine surface area in non-routine problems. They consider surface area of kitchen sponges, rock salt crystals, and...
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...
Illustrative Mathematics
Use Cavalieri’s Principle to Compare Aquarium Volumes
Learners are designing a stunning new water feature for an aquarium, but they soon discover that more than just a pretty home for their fishy friends is required. From calculating the volume of a composite shape through the abstract...
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...
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...
Mathed Up!
Sine and Cosine Rules and Area of Triangles
Learners discover how to find missing sides and angles using trigonometry. Scholars first watch a video covering the Law of Sines and Cosines, as well as the area formula for a triangle. To test their knowledge, they complete a worksheet...
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.
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...
Mathematics Vision Project
Module 5: Circles A Geometric Perspective
Circles, circles, everywhere! Pupils learn all about circles, central angles, inscribed angles, circle theorems, arc length, area of sectors, and radian measure using a set of 12 lessons. They then discover volume formulas through...
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?
Young scholars 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...
Curated OER
Geometry: Area Project
Sixth graders identify and use area formulas for finding the area of geometric shapes.
Concord Consortium
Circumscribed Polygon
Trigonometry teachers often go off on a tangent, and here's a activity that proves it! First, young mathematicians use a formula with tangent to prove a formula correct for area. Then, they draw conclusions about the area of a circle...
Curated OER
Volume and Surface Area
In this volume and surface area worksheet, 10th graders solve and complete 10 different problems that include using spheres to examine changes in volume and surface area. First, they complete the chart shown using the formulas given....
Radford University
Fun with Solids
Cakes offer a yummy way to learn about math. Scholars use manipulatives to discover the formulas for the surface area and volume of prisms and cylinders. They use their formulas to calculate the amount of cake mix and frosting necessary...
Curated OER
Finding Areas of Plane Figures
Students 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. In 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.
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 lesson plan 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 finding...