Question

answer this one please . no wrong answers please .​

Answer 1

Step-by-step explanation:

since AB = AC

<ABC=<ACB ......(1)

NOW, <ABC+<ACB+<BAC=180

==> 2<ABC+40=180 [by (1)]

==> <ABC=70 .......(2)

==> <ABD+<DBC=70

==> 30+ <DBC =70

==> <DBC =40 ....... ....(3)

also from (1) and (2)

<ACB=70 ....(4)

from triangle BDC

<DBC +<DCB+<BDC=180

==> 40+70+<BDC =180

==> <BDC =70 .....(5)

since <BDC=<DCB=70

THEN BC=BD (PROVED)