Drag a statement or reason to each box to complete this proof.


Given: the measure of angle A B D equals 60 degrees. The measure of angle D B C equals 40 degrees. Prove: triangle A B C is an obtuse triangle. Art: triangle A B C with horizontal base B C is drawn. A bisector B D is drawn on A C. The bisector divides A C into two parts A D and D C.


1. m∠ABD = 60°, m∠DBC=40° Given

2. m∠ABD + m∠DBC = m∠ABC ________

3. ______ Substitution Property of Equality

4. ______ Simplifying

5. ∠ABC is an obtuse angle. _________

6. △ABC is an obtuse triangle. Definition of obtuse triangle


Boxes needed to put in _________


100° = m∠ABC

60° + 40° = m∠ABC

Definition of obtuse angle

Angle Addition Postulate