1, the height of a triangle is ().

A, 1 B, 3 C, countless

2. If the acute angle of a right triangle is 20? Then the other corner must be ().

a、20？ b、70？ c、 160？

3. The tripod of bicycle uses the characteristics of triangle ().

A, stability B, characteristics with three sides C, easy to deform

4. All equilateral triangles are triangles.

A, acute angle b, obtuse angle c, right angle

5. In a triangle? 1= 120? ,? 2=36? ,? 3=( )

a、54？ b、24？ c、36？

6. At least () identical triangles can be used to form a trapezoid.

a、2 B、3 C、4

7. The sum of the inner angles of a rectangle is ().

a、90？ b、 180？ c、360？

Second, do as required.

1 Is it a triangle? , not a triangle painting? ○? .

( ) ( ) ( ) ( ) ( )

2. Draw under a stick that can be made into a triangle? . (Unit: cm)

( ) ( ) ( )

3. Score one point as required.

Acute triangle has () obtuse triangle has ()

Right triangle has () isosceles triangle has ()

4. Draw the height at the bottom of each triangle below.

5. Draw an isosceles triangle and a right triangle on the point diagram.

Third, find the degree of each corner of the triangle.

Fourth, solve the problem.

Can you explain why?

2. How many roads are there from the school to the Children's Palace? Which is the shortest way? Why?

3. An isosceles triangle billboard with a bottom angle of 65? What is its vertex angle?

Grandpa Wang has a vegetable field with an approximate equilateral triangle. If you put a fence around the vegetable field, what is the perimeter of the fence?

5. known? 1、? 2、? 3 is the three internal angles of triangle ABC. 1=48? ,

? 2=72? , beg? The degree of 3.

6. The following are fragments left by three triangular pieces of glass. Can you tell what triangles they were originally?