Question

Cho ΔMNP có: Góc P = 40 độ ; góc M = \(\dfrac{1}{2}\)góc N . Tính góc M ; góc N

Answer 1

Lời giải:

Theo định lý về tổng 3 góc trong tam giác:

$\widehat{M}+\widehat{N}=180^0-\widehat{P}=180^0-40^0=140^0$

Thay $\widehat{M}=\frac{1}{2}\widehat{N}$ vô thì:

$\frac{1}{2}\widehat{N}+\widehat{N}=140^0$

$\frac{3}{2}\widehat{N}=140^0$

$\Rightarrow \widehat{N}=\frac{280^0}{3}$

$\widehat{M}=\frac{1}{2}\widehat{N}=\frac{140^0}{3}$