CK-12 Geometry-Concepts

4.8. ASA and AAS Triangle Congruence http://www.ck12.org

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/1304

James Sousa: Determining If Two Triangles are Congruent

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/1317

James Sousa: Example 2: Prove Two Triangles are Congruent

Guidance

Consider the question: If I have two angles that are 45◦and 60◦and the side between them is 5 in, can I construct
only one triangle? We will investigate it here.

Investigation: Constructing a Triangle Given Two Angles and Included Side

Tools Needed: protractor, pencil, ruler, and paper

1. Draw the side (5 in) horizontally, halfway down the page.The drawings in this investigation are to scale.


2. At the left endpoint of your line segment, use the protractor to measure the 45◦angle. Mark this measurement
   and draw a ray from the left endpoint through the 45◦mark.


3. At the right endpoint of your line segment, use the protractor to measure the 60◦angle. Mark this measurement
   and draw a ray from the left endpoint through the 60◦mark. Extend this ray so that it crosses through the ray
   from Step 2.