Помогите срочно!!!!​

Question

Помогите срочно!!!!​

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Answer 1

АВ=8;АД=10
AC=BD
BD²=12²+8²=144+64=208=13*16
BD=√(13*16)=4√13
AO=OB=BD/2=2√13
∆AOB =>AB²=AO²+BO²-2*AO*BO*cosa

64=8*13-8*13*cosa
cosa=(104-64)/104=40/104=10/26=5/13
sina=√(1-25/169)=12/13
tga=12/13 :5/13=12/5
ctga=5/12