Triangles (7th grade) UNFINISHED LEARNING

Triangles (7th grade) UNFINISHED LEARNING

Write and solve an equation to find X.

Multiple Choice

Which equation can be used to solve for x?

• x + 50 = 180

• x - 50 = 180

• 180 + 50 = x

Vertical Angles

are congruent

share a common vertex

are opposite each other

Multiple Choice

Find the measure of x.

• 120

• 90

• 180

Triangles = 180 degrees

• 3 angles

• are measured by their sides and angles

• Impossible to have more than 1 right angle in a triangle.

• Impossible to have more than 1 obtuse angle in a triangle

Multiple Choice

Find the measure of angle b.

• 85

• 90

• 180

• 100

Multiple Choice

Find the measure of angle a

• 20

• 60

• 180

• 85

An infinite number of triangles can be created using the same three angle measures (e.g., there are many triangles with angles whose measures are 45○, 60○, and 75○).

Triangles and Side Lengths

• To form a triangle using side lengths, the sum of any two sides must be greater than the length of the third side. 

• Ex. 2cm, 3cm, 5cm will NOT make a traingle becuase 2 + 3 is NOT larger than the third side

• Ex. 3cm, 3cm, 5cm will make a triangle because 3 + 3 is larger than the length of the greratest side 5cm.

Multiple Choice

Can you draw a triangle with sides that are 13 cm, 5 cm and 6 cm?

• NO because 5 + 6 is not larger than 13

• YES because 5 + 6 is larger than the longest side

Multiple Choice

What would be the measure of the third angle in a triangle formed from these parts?

180 = 53 + 34 + x

• 180

• 87

• 93

Multiple Choice

Can line segments measuring 8, 5, 4 form a triangle?

• Yes. 4 + 5 > 8

• No. 4 + 5 < 8

Multiple Choice

Can a triangle be formed with 3 sides of equal lengths?

• Yes. Ex. 3 + 3 > 3

• No. 3 + 3 < 3