Question

please help me with no.6

Answer 1

Refer to this attachment.

⭐⭐Be Brainly⭐⭐

Answer 2

since
AB=AC
then
angle ABC = angle ACB, (since angle opposite to equal sides are equal),

let angle ABC=angle ACB=x,

now in ∆ABC, by angle sum property

40°+angle ABC + angle ACB=180°,

angleABC+angleACB=180°-40°,

x+x=140°,

then
x=70°

now
angle ABC=angle ABD + angle DBC,

70°=30°+angle DBC,

then
angle DBC=40°,

now
angle BDC=angle ABD+angle BAD, (by exterior angle property),

then
angle BDC=30° + 40°=70°

now in ∆BDC, using angle sum property,

angle BDC+angle BCD+angle DBC=180°,
70°+angle BCD+40°=180°,

angle BCD=180°-70°-40°,

angle BCD=180°-110°,

angle BCD=70°,



since

angle BDC=angle BCD=70°,

then
BD=BC (since sides opposite to equal angles are equal)