Question

Triangle ABC is shown below.
Given: ∆ABC
Prove: All three angles of ∆ABC add up to 180°.
The flow chart with missing reason proves the measures of the interior angles of ∆ABC total 180°.
Which reason can be used to fill in the numbered blank space?

Answer 1

options are:
Alternate Exterior Angles Theorem

Same-Side Interior Angles

Corresponding Angles Postulate

Alternate Interior Angles Theorem

Answer 2

For the triangle:
To see why the sum of the degrees of the angles on a triangle add
to 180 look at a rectangle. It has four angles each of 90
degrees. So the sum of its angles is 360 degrees.

Draw the diagonal of this rectangle and you will split the
rectangle into two triangles. Add up all the angles of the
triangles and you should get 360 degrees since the rectangle had
360 degrees (and we didn't expand the rectangle or anything).

Your triangles are exactly alike, so they must have the same

Answer 3

@PexVura i don't understand

Answer 4

i don't understand how you're flowchart works but i can tell you why the angle sum is 180
DE//AC=><DBA=<BAC and <EBC=BCA both pair are alternate interior
now <DBA+<ABC+<EBC=180 (straight line)
by substitution you get <BAC+<ABC+<BCA=180

Answer 5

u have to fill in the blank in the flow chart
and the options are:
Alternate Exterior Angles Theorem

Same-Side Interior Angles

Corresponding Angles Postulate

Alternate Interior Angles Theorem

Answer 6

then the last option

Answer 7

ok thanks!

Answer 8

np