1. 3.3 Constructions of Equilateral Triangles and Isosceles Right Triangles
TSWBAT:
Construct equilateral and isosceles right triangles

2. What do you know about the angles of an equilateral triangle?
Click to view
construction
Draw a segment AB.

3. 1. Mark a point P that will become one vertex of a triangle
2. Set the compass width to the desired length AB
3. From P, draw an arc near both the other vertices (corners)
4. Mark a point Q on either arc to be the next vertex.
5. Without changing the width, move to Q and draw an arc across the other, creating R.
6. Connect P, Q and R.

4. Equilateral Triangle Practice

5. An Isosceles Triangle Draw 2 segments AB and CD (CD will be the base)
Click to view
construction

6. 1. Mark a point P that will become one vertex of a triangle
2. Set the compass width to CD
3. From P, draw an arc
4. Mark a point R on the arc, PR will be the base of the triangle.
5. Connect P and R
6. Set the compass width to AB - the side length.
7. From P and R, make 2 arcs to make point Q.
8. Connect P, Q and R.

7. Isosceles Triangle Practice

8. An Isosceles Right triangle is... a right triangle with congruent legs
Angle measurements would be 45, 45 and 90.
leg
hypotenuse
Click to view
construction

9. 1. Draw the line PQ to be one leg of the triangle
2. Create a perpendicular bisector
3. Label the midpoint R, and set the compass width to PR
4. Draw an arc across the perpendicular creating C.
5. Connect P and C.
* Triangle PCR is a right isosceles triangle

10. Isoscelese Right Triangle Practice

11. Construct a triangle, which angles measure 30 , 60 ,and 90 .
leg
hypotenuse 30 60
How do you construct this triangle?
1. make an equilateral triangle
2. create perpendicular bisector on one side of the triangle

12. 30 - 60 - 90 Right Triangle Practice