Prove that the sum of the measures of the interior angles of a triangle is 180°. Be sure to create and name the appropriate geometric figures.

Question

danjs · Answer

You can use parallel lines and a transversal if that works for you

danjs · Answer

|dw:1438046185578:dw|

danjs · Answer

|dw:1438046248433:dw|

danjs · Answer

did you learn about those things?

anonymous · Answer

of coarse

danjs · Answer

ok fill out equivalent angles somewhere so that a b and c form a line

danjs · Answer

move a to its corresponding angle, and move c to the alternate interior

danjs · Answer

|dw:1438046415721:dw|

anonymous · Answer

so c is the intersecting point now?

danjs · Answer

they want you to show that the angles (a + b + c) = 180

danjs · Answer

using the parallel line and transversal line, you can arrange angles a b and c to make a line, which is 180 degrees

anonymous · Answer

okay so this now would be a straight proving they equal 180

danjs · Answer

yes

anonymous · Answer

okay thank you

danjs · Answer

you can say...

danjs · Answer

|dw:1438046829479:dw|

danjs · Answer

A + C is supplmntary to B , so A + B + C must be 180

anonymous · Answer

yes that makes sense