EngageNY
Composite Area Problems
The 21st segment in a 28-part series provides learners with area problems involving composite figures. To find the solution, pupils must decide whether to add or subtract areas. The composite figures are composed of quadrilaterals,...
Curated OER
Developing Formulas for Triangles and Quadrilaterals
In this geometry worksheet, 10th graders determine the area of triangles, parallelograms, trapezoids, kites, and rhombuses. The one page worksheet contains eleven problems. Answers are included.
Illustrative Mathematics
Finding Areas of Polygons, Variation 1
An exercise in finding the area of polygons by decomposing into triangles and composing into rectangles is the focus of this resource. Make several copies of the worksheet for each participant. Ask learners to use colored pencils to...
Alaska Department of Education
Mathematics Reference Sheet
Triangles and prisms don't stand a chance when your learners use this handout full of the formulas they need to know about the different shapes. Area, volume, and surface formulas are all covered along with the standard measurement and...
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...
101 Questions
Best Triangle
What makes an equilateral triangle equilateral? It turns out it's much more than just the side lengths! Learners analyze four different triangles to determine the best equilateral triangle. They create a formula that they later use to...
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...
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
Finding the Area of Shapes
In this area of shapes unit, upper graders participate in hands-on problem solving activities to find the formulas for the area of a parallelogram, a triangle, and a trapezoid. They manipulate the geoboard to explore relationships among...
Curated OER
Area and Perimeter
Another good presentation by Christine Berg is here for you. In it, learners are coached on definitions of area and perimeter and are shown how to perform calculations for both. They also see how to calculate the area of a triangle by...
CK-12 Foundation
Determination of Unknown Triangle Measures Given Area: Jib Sheets
Solving triangles is a breeze. Young boat enthusiasts solve problems involving triangles in the context of sails on a boat. They must apply different strategies, including the Law of Cosines and area formulas.
Hotchalk
Triangle Sum Theorem
Your visual geometry learners will appreciate triangle drawings as they model the triangle sum theorem and algebraically solve to find the missing interior angle in a triangle. Practice problems increase in complexity and vary in their...
Curated OER
Area, Perimeter, Volume Formulas
In this formulas instructional activity, students write the area, perimeter, and volume formulas of 17 2D and 3D polygons. Students list properties of various types of triangles and the metric conversions for metric units.
Del Mar College
Formulas for Elementary and Intermediate Algebra
Give your scholars the support they need to work with formulas. A reference page offers definitions and picture examples of perimeter, area, surface area, volume, the Pythagorean theorem, a variety of shapes, and more.
Concord Consortium
Strings and Areas
You'd be surprised what you can do with a string! The constraint is the length of string, and the task is to maximize area. Given a series of composite shapes, learners must create a formula for the maximum area for a specified...
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...
Flipped Math
Parallelograms and Triangles
Expand area problems to incorporate prior knowledge. Pupils begin by reviewing the formulas for finding the area of parallelograms and triangles. The scholars apply previous learning of trigonometric ratios and the Pythagorean Theorem to...
Flipped Math
Unit 9 Review: Area of Polygons
It's time to show what you know! Individuals first review finding the area of polygons using the formulas from parallelograms to regular polygons. They then brush up on finding the area and circumference of circles, as well as reviewing...
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.
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
Unknown Area Problems on the Coordinate Plane
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...
CK-12 Foundation
Alternate Formula for the Area of a Triangle: Alternate Area of a Triangle
It's always nice to have a plan B. Pupils investigate an alternate formula for the area of a triangle that uses sine. A set of challenge questions shows how the new formula relates to the well-known formula of (1/2)bh.
EngageNY
The Volume Formula of a Pyramid and Cone
Our teacher told us the formula had one-third, but why? Using manipulatives, classmates try to explain the volume formula for a pyramid. After constructing a cube with six congruent pyramids, pupils use scaling principles from...
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.