a) Ta có tam giác MNP cân tại M => \(\widehat{N}=\widehat{P}\)

mà \(\widehat{M}+\widehat{N}+\widehat{P}=180^0\)

\(=>\widehat{N}+\widehat{P}=180^0-\widehat{M}=180^0-65^0=115^0\)

\(=>\widehat{N}=\widehat{P}=115^0:2=57,5^0\)

b) Ta có \(\widehat{N}=\widehat{P}\left(cmt\right)\)

\(=>\widehat{P}=50^0\)

Mà \(\widehat{M}+\widehat{N}+\widehat{P}=180^0\)

\(=>\widehat{M}=180^0-\left(\widehat{N}+\widehat{P}\right)=180^0-\left(50^0+50^0\right)=180^0-100^0=80^0\)

\(\widehat{P}=180^0-2\cdot70^0=40^0\)

40^o

a. tam giác ABC vg tại A suy ra B+C=90 suy ra B=90-40=50

b. từ đề bài suy ra N+P=180-75=105 và N=P=(N+P)/2=......

Vì Tam giác `MNP` cân tại `M -> MN = MP,` \(\widehat{N}=\widehat{P}\)

Mà `MN= 3 cm, `\(\widehat{N}=60^0\)

`-> MN = MP = 3 cm, `\(\widehat{N}=\widehat{P}=60^0\)

Xét Tam giác `MNP:`

\(\widehat{M}+\widehat{N}+\widehat{P}=180^0\)

`->`\(\widehat{M}+60^0+60^0=180^0\) 

`->`\(\widehat{M}=60^0\)

Ta có:

\(\widehat{M}=\widehat{N}=\widehat{P}=60^0\)

`->` \(\text {Tam giác MNP là tam giác đều}\)

`-> MN = MP = NP = 3 cm.`

N= 50 độ

\(\widehat{N}=\dfrac{180^0-50^0}{2}=65^0\)

N=50 độ

BO là phân giác của góc ABC

=>\(\widehat{OBC}=\dfrac{1}{2}\cdot\widehat{ABC}\)

CO là phân giác của góc ACB

=>\(\widehat{OCB}=\dfrac{1}{2}\cdot\widehat{ACB}\)

Xét ΔBOC có \(\widehat{BOC}+\widehat{OBC}+\widehat{OCB}=180^0\)

=>\(\widehat{OBC}+\widehat{OCB}=180^0-120^0=60^0\)

=>\(\dfrac{1}{2}\left(\widehat{ABC}+\widehat{ACB}\right)=60^0\)

=>\(\widehat{ABC}+\widehat{ACB}=120^0\)

Xét ΔABC có \(\widehat{ABC}+\widehat{ACB}+\widehat{BAC}=180^0\)

=>\(\widehat{BAC}+120^0=180^0\)

=>\(\widehat{BAC}=60^0\)

ΔABC=ΔMNP

=>\(\widehat{M}=\widehat{BAC}=60^0\)

\(a,\widehat{M}=90^o\\ \Rightarrow\widehat{N}+\widehat{P}=90^o\\ M\text{à}:\widehat{N}:\widehat{P}=3:2\Rightarrow\widehat{N}=1,5\widehat{P}\\ \Rightarrow1,5\widehat{P}+\widehat{P}=90^o\\ \Leftrightarrow\widehat{P}=36^o;\widehat{N}=54^o\)

\(b,\widehat{M}+\widehat{N}+\widehat{P}=180^o\\ M\text{à}:\widehat{M}=80^o\\ \Rightarrow\widehat{N}+\widehat{P}=100^o\\ M\text{à}:\widehat{N}+2\widehat{P}=120^o\\ \Rightarrow\widehat{P}=20^o;\widehat{N}=80^o\\ c,\widehat{M}:\widehat{N}:\widehat{P}=2:1:6\\ M\text{à}:\widehat{M}+\widehat{N}+\widehat{P}=180^o\\ \Leftrightarrow9\widehat{N}=180^o\\ \Leftrightarrow\widehat{N}=20^o\\ \Rightarrow\widehat{M}=2\widehat{N}=2.20^o=40^o\\ \widehat{P}=6.\widehat{N}=6.20^o=120^o\)

a: Ta có: ΔNMP cân tại N

=>\(\widehat{NMP}=\widehat{NPM}=\dfrac{180^0-\widehat{N}}{2}\)

=>\(\widehat{NMP}=\widehat{NPM}=\dfrac{180^0-76^0}{2}=52^0\)

b: ΔMNP cân tại N

=>\(\widehat{M}=\widehat{P}\)

mà \(\widehat{M}=47^0\)

nên \(\widehat{P}=47^0\)

Ta có: ΔMNP cân tại N

=>\(\widehat{N}=180^0-2\cdot\widehat{M}\)

=>\(\widehat{N}=180^0-2\cdot47^0=180^0-94^0=86^0\)