This task examines the ways in which the plane can be covered by regular polygons in a very strict arrangement called a regular tessellation. These tessellations are studied here using algebra, which enters the picture via the formula for the measure of the interior angles of a regular polygon (which should therefore be introduced or reviewed before beginning the task). The goal of the task is to use algebra in order to understand which tessellations of the plane with regular polygons are possible.

Students play and record the “Mary Had a Little Lamb” song using musical instruments and analyze the intensity of the sound using free audio editing and recording software. Then they use hollow Styrofoam half-spheres as acoustic mirrors (devices that reflect and focus sound), determine the radius of curvature of the mirror and calculate its focal length. Students place a microphone at the acoustic mirror focal point, re-record their songs, and compare the sound intensity on plot spectrums generated from their recordings both with and without the acoustic mirrors. A worksheet and KWL chart are provided.

In this lesson students use problem-solving strategies and a plan to solve real-world dilemmas. Students watch a video tutorial, explore guided notes and attempt practice problems.

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In this lesson students use the Pythagorean Theorem to find lengths and distances. Students watch a video tutorial, explore guided notes and attempt practice problems.

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In this lesson students use the Pythagorean Theorem to find lengths and distances. Students watch a video tutorial, explore guided notes and attempt practice problems.

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Use the strategies of making a table and looking for a pattern to solve problems.

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Given the coordinates of two points, use the Distance Formula to find the distance between them. Students examine guided notes, review guided practice, watch instructional videos and attempt practice problems.

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This concept introduces the distance formula and uses it to prove that line segments are congruent. Students examine guided notes, review guided practice, watch instructional videos and attempt practice problems.

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In this lesson students learn how to use the distance formula. Students examine guided notes, review guided practice, watch instructional videos and attempt practice problems.

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In this lesson students learn how to use the distance formula. Students examine guided notes, review guided practice, watch instructional videos and attempt practice problems.

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Learn how to solve problems using scale and indirect measurement.

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In this game activity students practice comparing shapes and naming something that is alike or different about them.

Are your students having difficulty understanding math terminology? Try this A-Z glossary on math related terms. It's quick, easy to read, and very complete.

This task provides a construction of the angle bisector of an angle by reducing it to the bisection of an angle to finding the midpoint of a line segment. It is worth observing the symmetry -- for both finding midpoints and bisecting angles, the goal is to cut an object into two equal parts. The conclusion of this task is that they are, in a sense, of exactly equivalent difficulty -- bisecting a segment allows us to bisect and angle (part a) and, conversely, bisecting an angle allows us to bisect a segment (part b). In addition to seeing how these two constructions are related, the task also provides an opportunity for students to use two different triangle congruence criteria: SSS and SAS.

This short video and interactive assessment activity is designed to give fourth graders an overview of classification of angles.

This short video and interactive assessment activity is designed to give fourth graders an overview of measurement of angles.

Find out how angles and symmetry come into play in the game of pool in this video adapted from Annenberg Learner’s Learning Math: Measurement.

The famous story of Archimedes running through the streets of Syracuse (in Sicily during the third century bc) shouting ''Eureka!!!'' (I have found it) reportedly occurred after he solved this problem. The problem combines the ideas of ratio and proportion within the context of density of matter.

In this problem, students are given a picture of two triangles that appear to be similar, but whose similarity cannot be proven without further information. Asking students to provide a sequence of similarity transformations that maps one triangle to the other focuses them on the work of standard G-SRT.2, using the definition of similarity in terms of similarity transformations.