Geometrical Reasoning - Similar and Congruent Triangles
Key Stage: 4 ★★★
A carpenter's square allows you to trisect an angle. Can you explain why it works?
This problem utilises congruent triangles to provide a simple proof. There are opportunities for discussion of "why it works" and for drawing upon the historical context of angle trisection as well as considering extending the idea to obtuse angles. You might wish to use this problem after you have completed some work on congruence tests (see notes below).
This resource has comprehensive teachers' notes and resources, linked from the problem page. This includes possible approaches and key questions, as well as possible support and extensions.
The file attached is a HTML file, which, when opened, automatically redirects you to the problem on the NRICH website.
Key Stage: 4 ★★★
A carpenter's square allows you to trisect an angle. Can you explain why it works?
This problem utilises congruent triangles to provide a simple proof. There are opportunities for discussion of "why it works" and for drawing upon the historical context of angle trisection as well as considering extending the idea to obtuse angles. You might wish to use this problem after you have completed some work on congruence tests (see notes below).
This resource has comprehensive teachers' notes and resources, linked from the problem page. This includes possible approaches and key questions, as well as possible support and extensions.
The file attached is a HTML file, which, when opened, automatically redirects you to the problem on the NRICH website.
Something went wrong, please try again later.
This resource hasn't been reviewed yet
To ensure quality for our reviews, only customers who have downloaded this resource can review it
Report this resourceto let us know if it violates our terms and conditions.
Our customer service team will review your report and will be in touch.
£0.00