1. Measuring Angles
Discuss with your group what the following words mean and write them in your journal:
Acute Angle
Obtuse Angle
Right Angle
Straight Angle

6. Classifying Triangles

7. Copy this into your journal.

8. Copy this in your journal.

9. Look at the following set of triangles and create a list of observations about the triangles that you see.
Be sure to pay attention to the sum of the angles, and how the angles relate to the length of the sides.

11. Important things to remember about triangles:
The angles always add up to 180 degrees.
If there are congruent angles, then there will be 2 congruent sides. (Isosceles triangle)
If it is an equivalent triangle, all 3 sides are equal. What about the angles? Are they equal? What will they be?

12. One more thing to think about…
Every triangle has at least 2 acute angles.
The third angle determines the type of triangle that it is.
If there are 2 acute angles and 1 obtuse angles, it is an obtuse triangle.
If there are 2 acute angles and 1 right angle, it is a right triangle.
It is only an acute triangle if all 3 angles are acute.

13. How can you find the total measure of the angles in this triangle?
What do you know about
the measure of angles
A and B?
How can you find the total measure of the angles in this triangle? B 70 A

19. Classifying Quadrilaterals

20. What do you notice about the angles in a quadrilateral?

21. A rectangle is a quadrilateral with 4 right angles.
It has 2 pairs of parallel sides.

22. Square
A quadrilateral with 4 right angles and 4 congruent sides.

23. A quadrilateral that has 4 congruent sides.
Rhombus
A quadrilateral that has 4 congruent sides.
There are 2 pairs of parallel sides.
Does a rhombus have right angles?
Can a rhombus have right angles?

24. Parallelogram
A quadrilateral with 2 pairs of parallel sides.
The opposite sides are congruent.

25. A quadrilateral with only 1 pair of parallel sides.
Trapezoid
A quadrilateral with only
1 pair of parallel sides.
(Think about an elephant that is trapped!)

26. What do you know about the relationship between angles x and y?
about the measures
of angles x, y, and z?
How can you find the total measures of the angles in this parallelogram?
What do you know about the relationship between angles x and y? Z Y 70 A

27. How can you find the total measure of the angles in this trapezoid?
What do you know
about the measures
of angles R, P, and Q?
How can you find the total measure of the angles in this trapezoid?
What do you know about this shape?
130 P Q R

28. How can you find the total measure of the angles in this trapezoid?
What is this shape?
What do you know about
the measure of angle M?
How can you find the total measure of the angles in this trapezoid? M 61

29. How can you determine if the sides of a quadrilateral are parallel?
How can you determine if an angle is a right angle?
How can you determine if the sides are congruent?

30. What is an attribute that all quadrilaterals share?
Why can we say that all parallelograms are quadrilaterals, but we cannot say that all quadrilaterals are parallelograms?
How could you describe a square in terms of a parallelogram?
How could you describe a square in terms of a rhombus?