Question

abc is a triangle in which DE/./BC,find angle a​

Answer 1

Answer:

angle A is

45degree

Step-by-step explanation:

We know that

sum of angles of a triangle is 180 degree

.

in triangle BEC

angle C =180-(30+80)=180-120=60 degree

DE|| BC

angle EBC =angle DEB=30..(alternate angles)

in triangle DEB

angle DBE=180-(30+105)=180-135=45 degree

angle ABC=angleDBE+angleEBC=45+30=75 degree

in triangle ABC

angles (A+B+C)=180 degree

angle A=180-(75+60)=180-135=45 degree