Nguyễn Huy Giáp
Giới thiệu về bản thân
よっ、ハガネです。
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2025-09-27 18:30:36
Xét △ABC, có:
\(A+B+C=180^{\circ}\)
\(A=180^{\circ}-\left(\right.65^{\circ}+45^{\circ}\left.\right)=70^{\circ}\)
Lại có:
\(\frac{AB}{\sin C}=\frac{AC}{\sin B}=\frac{BC}{\sin A}\)
hay \(\frac{AB}{\sin C}=\frac{2,8}{\sin45^{\circ}}\thickapprox3,96\)
\(\rArr AC=\sin65^{\circ}\times3,96\thickapprox3,59\operatorname{cm}\)
\(\rArr BC=\sin70^{\circ}\times3,96\thickapprox3,72\operatorname{cm}\)
Vậy \(\hat{A}=70^{\circ}\) ; \(AC\thickapprox3,59\operatorname{cm}\) ; \(BC\thickapprox3,72\operatorname{cm}\)