Помогите срочно!!!!!!

Question

Помогите срочно!!!!!!

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Answer 1

HR=ER-FK=8-4=4;
KH=FE=4√3;
tg∠R=KH/HR=4√3/4=√3;
KR=√(KH²+HR²)=√(48+16)=√64=8;
sin∠R=KH/HR=4√3/8=√3/2;⇒
∠R=60°;