Texas Instruments
Texas Instruments: Triangulation Problem
In this Computer Algebra System (CAS) activity, students use 'landscape' paper and fold the top left corner of the page so that it just touches the bottom of the page. They calculate the area of the triangle formed by the bottom left...
Maths Challenge
Maths challenge.net: Shaded Square
A problem of finding the fraction of a square that is shaded given criterion. Students will have to use their mathematical reasoning and triangle solving skills to solve this area problem.
Purple Math
Purplemath: Determinant Word Problems
Matrix determinants can be used to solve many algebra and geometry word problems. Among them: finding the area of a triangle, finding the area of a parallelogram, and finding the equation of a line between two points. These three...
Illustrative Mathematics
Illustrative Mathematics: G C, G Srt Setting Up Sprinklers
In this task, students must decide where to place sprinklers on a lawn so that the maximum area of the lawn will be watered. To solve it, they must find areas of sectors of circles and use trigonometric ratios to solve right triangles....
Calculator Soup
Calculator Soup: Isosceles Triangles Calculator
Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.
Maths Challenge
Maths challenge.net: Maximum Square
A challenging proof like geometry of finding the square inscribed in a triangle.
Texas Instruments
Texas Instruments: Heron's Formula
This activity allows students to find the area of a triangle using Heron's formula.
Other
The mathlab.com: Sophia's Tree of Mysteries
There are 10 questions hidden in the tree. Click around to find them. As you find each answer, use the decoder grid below to find its matching letter to determine the required password to enter the restricted area.
Texas Instruments
Texas Instruments: Numb3 Rs: Location! Location! Location!
Based off of the hit television show NUMB3RS, this lesson introduces students to Voronoi diagrams, which split a plane into regions corresponding to distances to given points. The lesson is framed in the context of splitting a city into...
CK-12 Foundation
Ck 12: Geometry: Applications of the Pythagorean Theorem
[Free Registration/Login may be required to access all resource tools.] In this lesson students use the Pythagorean Theorem to find perimeter and area. Students examine guided notes, review guided practice, watch instructional videos and...