What is your angle ?
(activity 2)
What is your angle ?
 Please research “what is your angle?”
 Find the relationship between angles and
sides?
 Find different triangles.
 Avaliable web sites:
Nettrekker.com
What is your angle ?
 1. Cut out the four triangles from
Figure 1.
 2. Compare the attributes of ΔABC ,
ΔDEF and ΔGHI ; list the similarities and
differences
 3. If each square measures 1 square
centimeter, then what is the measure of
the lengths of the sides of the following
triangles?
What is your angle ?
 4. Set up ratios of the long leg to the
short leg of ΔABC and the long leg to
short leg of ΔDEF .Determine if these
ratios are equal.
 5. Set up ratios of the long leg to the
hypotenuse of ΔABC and the long leg to
the hypotenuse of ΔDEF . Determine if
these ratios are equal.
What is your angle ?
 6. Set up ratios of the short leg to the
hypotenuse of ΔABC and the short leg to the
hypotenuse of ΔDEF . Determine if these ratios
are equal.
 7. Repeat steps 4-6 with ΔABC and ΔGHI .
 8. Repeat steps 4-6 with ΔDEF and ΔGHI .
 9. Summarize what you have discovered about
the angles and sides of ΔABC , ΔDEF , and
ΔGHI
What is your angle ?
 10. Now compare the attributes of
triangle ΔJKL to the attributes of the other
three triangles. What do you notice? Is
there anything that is the same? Is there
anything that is different?
 11. Look at the following pairs of
triangles. Determine if each pair of
triangles is similar.
What is your angle ?
 12. What do you notice about the angles in each pair of
triangles?
 13. The investigation explored a postulate called the
Angle-Angle Similarity Postulate for triangles. Make a
conjecture about what you think this postulate would
say.
 14. Explain why we are allowed to call it the AngleAngle Similarity postulate and do not have
to call it the Angle-Angle-Angle Similarity Postulate.
(MTC math TEKS connections Geometry Student
Lessons)
What is your angle ?
 Practice or Homework:
 http://argyll.epsb.ca/jreed/math9/strand3/triangl
e_congruent.htm
 http://www.analyzemath.com/Geometry/similar
_triangles.html
 http://www.analyzemath.com/Geometry/similar
_triangle_problems.html
 http://my.hrw.com/math06_07/nsmedia/homew
ork_help/msm3/msm3_ch05_07_homeworkhel
p.html
References
 http://my.hrw.com/math06_07/nsmedia/homework_help
/msm3/msm3_ch05_07_homeworkhelp.html
 Similar Triangles
References
 http://www.analyzemath.com/Geometry/si
milar_triangle_problems.html
References
 Texas A&M University (College of
Education and Human Development)
Funded by the Texas Education Agency
MTC math TEKS connections Geometry
student lessons